Can't get the ZAP browser to start.
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Henrik
Nov 14, 2025, 12:03:34 PM (4 days ago) Nov 14
to ZAP User Group
1. I updated my whole system (apt update, apt upgrade)
2. I updated my geckodriver from 0.34.0 to 0.36.0 and have it in /usr/bin as well as /usr/local/bin. The later of which is the one in use in my terminal and set in zaproxy.
3. tried using the provided geckodriver and not setting a path for firefox in the selenium settings
4. set an explicit path for firefox in the selenium settings and using my own geckodriver.
5. restartet my systsem after each step
6. reinstalled zap multiple times (including manually deleting the .ZAP directory)
7. updated my java jdk from 21 to 25, as adviced by java.
Tried to launch the zap browser after every step and in every configuration imaginable.
On the GUI:
The provided browser was not found.
See https://www.zaproxy.org/faq/no-browser/
I of course followed all steps in the faq. Also tried using google and generative ai. Nothing useful
In the log file:
2025-11-14 17:39:27,326 [AWT-EventQueue-0] INFO Control - New Session
2025-11-14 17:39:27,331 [AWT-EventQueue-0] INFO Control - Create and Open Untitled Db
2025-11-14 17:46:55,003 [ZAP-BrowserLauncher] ERROR ExtensionQuickStartLaunch - Could not start a new session. Possible causes are invalid address of the remote server or browser start-up failure. null
Host info: host: 'REDACTED', ip: '127.0.1.1'
Build info: version: '4.37.0', revision: '3c1da1e342'
System info: os.name: 'Linux', os.arch: 'amd64', os.version: '6.16.8+kali-amd64', java.version: '25.0.1'
Driver info: org.openqa.selenium.firefox.FirefoxDriver
Command: [null, newSession {capabilities=[Capabilities {acceptInsecureCerts: true, browserName: firefox, moz:firefoxOptions: {binary: /usr/bin/firefox-esr, prefs: {browser.tabs.documentchannel: false, dom.serviceWorkers.enabled: true, network.captive-portal-service.enabled: false, network.proxy.allow_hijacking_localhost: true, network.proxy.http: localhost, network.proxy.http_port: 8080, network.proxy.no_proxies_on: , network.proxy.share_proxy_settings: true, network.proxy.ssl: localhost, network.proxy.ssl_port: 8080, network.proxy.type: 1, remote.active-protocols: 1}}, webSocketUrl: true}]}]
org.openqa.selenium.SessionNotCreatedException: Could not start a new session. Possible causes are invalid address of the remote server or browser start-up failure. null
Host info: host: 'REDACTED', ip: '127.0.1.1'
Build info: version: '4.37.0', revision: '3c1da1e342'
System info: os.name: 'Linux', os.arch: 'amd64', os.version: '6.16.8+kali-amd64', java.version: '25.0.1'
Driver info: org.openqa.selenium.firefox.FirefoxDriver
Command: [null, newSession {capabilities=[Capabilities {acceptInsecureCerts: true, browserName: firefox, moz:firefoxOptions: {binary: /usr/bin/firefox-esr, prefs: {browser.tabs.documentchannel: false, dom.serviceWorkers.enabled: true, network.captive-portal-service.enabled: false, network.proxy.allow_hijacking_localhost: true, network.proxy.http: localhost, network.proxy.http_port: 8080, network.proxy.no_proxies_on: , network.proxy.share_proxy_settings: true, network.proxy.ssl: localhost, network.proxy.ssl_port: 8080, network.proxy.type: 1, remote.active-protocols: 1}}, webSocketUrl: true}]}]
at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:578) ~[selenium-remote-driver-4.37.0.jar:?]
at org.openqa.selenium.remote.RemoteWebDriver.startSession(RemoteWebDriver.java:246) ~[selenium-remote-driver-4.37.0.jar:?]
at org.openqa.selenium.remote.RemoteWebDriver.<init>(RemoteWebDriver.java:174) ~[selenium-remote-driver-4.37.0.jar:?]
at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:137) ~[selenium-firefox-driver-4.37.0.jar:?]
at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:132) ~[selenium-firefox-driver-4.37.0.jar:?]
at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:114) ~[selenium-firefox-driver-4.37.0.jar:?]
at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:109) ~[selenium-firefox-driver-4.37.0.jar:?]
at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:94) ~[selenium-firefox-driver-4.37.0.jar:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getWebDriverImpl(ExtensionSelenium.java:1175) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getWebDriver(ExtensionSelenium.java:968) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getWebDriver(ExtensionSelenium.java:936) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.internal.BuiltInSingleWebDriverProvider.getWebDriver(BuiltInSingleWebDriverProvider.java:63) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getWebDriverImpl(ExtensionSelenium.java:816) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getWebDriver(ExtensionSelenium.java:616) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getProxiedBrowser(ExtensionSelenium.java:777) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getProxiedBrowserByName(ExtensionSelenium.java:717) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getProxiedBrowserByName(ExtensionSelenium.java:693) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getProxiedBrowserByName(ExtensionSelenium.java:677) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getProxiedBrowserByName(ExtensionSelenium.java:667) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.quickstart.launch.ExtensionQuickStartLaunch.lambda$launchBrowser$1(ExtensionQuickStartLaunch.java:221) [quickstart-release-52.zap:?]
at java.base/java.lang.Thread.run(Thread.java:1474) [?:?]
Caused by: java.io.UncheckedIOException: java.net.ConnectException
at org.openqa.selenium.remote.http.jdk.JdkHttpClient.execute0(JdkHttpClient.java:500) ~[?:?]
at org.openqa.selenium.remote.http.AddSeleniumUserAgent.lambda$apply$0(AddSeleniumUserAgent.java:42) ~[?:?]
at org.openqa.selenium.remote.http.Filter.lambda$andFinally$1(Filter.java:55) ~[?:?]
at org.openqa.selenium.remote.http.jdk.JdkHttpClient.lambda$executeAsync$2(JdkHttpClient.java:387) ~[?:?]
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:545) ~[?:?]
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:328) ~[?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1090) ~[?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:614) ~[?:?]
... 1 more
Caused by: java.net.ConnectException
at java.net.http/jdk.internal.net.http.HttpClientImpl.send(HttpClientImpl.java:923) ~[java.net.http:?]
at java.net.http/jdk.internal.net.http.HttpClientFacade.send(HttpClientFacade.java:133) ~[java.net.http:?]
at org.openqa.selenium.remote.http.jdk.JdkHttpClient.execute0(JdkHttpClient.java:459) ~[?:?]
at org.openqa.selenium.remote.http.AddSeleniumUserAgent.lambda$apply$0(AddSeleniumUserAgent.java:42) ~[?:?]
at org.openqa.selenium.remote.http.Filter.lambda$andFinally$1(Filter.java:55) ~[?:?]
at org.openqa.selenium.remote.http.jdk.JdkHttpClient.lambda$executeAsync$2(JdkHttpClient.java:387) ~[?:?]
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:545) ~[?:?]
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:328) ~[?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1090) ~[?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:614) ~[?:?]
... 1 more
Caused by: java.net.ConnectException
at java.net.http/jdk.internal.net.http.common.Utils.toConnectException(Utils.java:1070) ~[java.net.http:?]
at java.net.http/jdk.internal.net.http.PlainHttpConnection.connectAsync(PlainHttpConnection.java:223) ~[java.net.http:?]
at java.net.http/jdk.internal.net.http.PlainHttpConnection.checkRetryConnect(PlainHttpConnection.java:277) ~[java.net.http:?]
at java.net.http/jdk.internal.net.http.PlainHttpConnection.lambda$connectAsync$0(PlainHttpConnection.java:235) ~[java.net.http:?]
at java.base/java.util.concurrent.CompletableFuture.uniHandle(CompletableFuture.java:955) ~[?:?]
at java.base/java.util.concurrent.CompletableFuture$UniHandle.tryFire(CompletableFuture.java:932) ~[?:?]
at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:531) ~[?:?]
at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1794) ~[?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1090) ~[?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:614) ~[?:?]
... 1 more
Caused by: java.nio.channels.ClosedChannelException
at java.base/sun.nio.ch.SocketChannelImpl.ensureOpen(SocketChannelImpl.java:204) ~[?:?]
at java.base/sun.nio.ch.SocketChannelImpl.connect(SocketChannelImpl.java:942) ~[?:?]
at java.net.http/jdk.internal.net.http.PlainHttpConnection.connectAsync(PlainHttpConnection.java:211) ~[java.net.http:?]
at java.net.http/jdk.internal.net.http.PlainHttpConnection.checkRetryConnect(PlainHttpConnection.java:277) ~[java.net.http:?]
at java.net.http/jdk.internal.net.http.PlainHttpConnection.lambda$connectAsync$0(PlainHttpConnection.java:235) ~[java.net.http:?]
at java.base/java.util.concurrent.CompletableFuture.uniHandle(CompletableFuture.java:955) ~[?:?]
at java.base/java.util.concurrent.CompletableFuture$UniHandle.tryFire(CompletableFuture.java:932) ~[?:?]
at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:531) ~[?:?]
at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1794) ~[?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1090) ~[?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:614) ~[?:?]
... 1 more
2. I updated my geckodriver from 0.34.0 to 0.36.0 and have it in /usr/bin as well as /usr/local/bin. The later of which is the one in use in my terminal and set in zaproxy.
3. tried using the provided geckodriver and not setting a path for firefox in the selenium settings
4. set an explicit path for firefox in the selenium settings and using my own geckodriver.
5. restartet my systsem after each step
6. reinstalled zap multiple times (including manually deleting the .ZAP directory)
7. updated my java jdk from 21 to 25, as adviced by java.
Tried to launch the zap browser after every step and in every configuration imaginable.
On the GUI:
The provided browser was not found.
See https://www.zaproxy.org/faq/no-browser/
I of course followed all steps in the faq. Also tried using google and generative ai. Nothing useful
In the log file:
2025-11-14 17:39:27,326 [AWT-EventQueue-0] INFO Control - New Session
2025-11-14 17:39:27,331 [AWT-EventQueue-0] INFO Control - Create and Open Untitled Db
2025-11-14 17:46:55,003 [ZAP-BrowserLauncher] ERROR ExtensionQuickStartLaunch - Could not start a new session. Possible causes are invalid address of the remote server or browser start-up failure. null
Host info: host: 'REDACTED', ip: '127.0.1.1'
Build info: version: '4.37.0', revision: '3c1da1e342'
System info: os.name: 'Linux', os.arch: 'amd64', os.version: '6.16.8+kali-amd64', java.version: '25.0.1'
Driver info: org.openqa.selenium.firefox.FirefoxDriver
Command: [null, newSession {capabilities=[Capabilities {acceptInsecureCerts: true, browserName: firefox, moz:firefoxOptions: {binary: /usr/bin/firefox-esr, prefs: {browser.tabs.documentchannel: false, dom.serviceWorkers.enabled: true, network.captive-portal-service.enabled: false, network.proxy.allow_hijacking_localhost: true, network.proxy.http: localhost, network.proxy.http_port: 8080, network.proxy.no_proxies_on: , network.proxy.share_proxy_settings: true, network.proxy.ssl: localhost, network.proxy.ssl_port: 8080, network.proxy.type: 1, remote.active-protocols: 1}}, webSocketUrl: true}]}]
org.openqa.selenium.SessionNotCreatedException: Could not start a new session. Possible causes are invalid address of the remote server or browser start-up failure. null
Host info: host: 'REDACTED', ip: '127.0.1.1'
Build info: version: '4.37.0', revision: '3c1da1e342'
System info: os.name: 'Linux', os.arch: 'amd64', os.version: '6.16.8+kali-amd64', java.version: '25.0.1'
Driver info: org.openqa.selenium.firefox.FirefoxDriver
Command: [null, newSession {capabilities=[Capabilities {acceptInsecureCerts: true, browserName: firefox, moz:firefoxOptions: {binary: /usr/bin/firefox-esr, prefs: {browser.tabs.documentchannel: false, dom.serviceWorkers.enabled: true, network.captive-portal-service.enabled: false, network.proxy.allow_hijacking_localhost: true, network.proxy.http: localhost, network.proxy.http_port: 8080, network.proxy.no_proxies_on: , network.proxy.share_proxy_settings: true, network.proxy.ssl: localhost, network.proxy.ssl_port: 8080, network.proxy.type: 1, remote.active-protocols: 1}}, webSocketUrl: true}]}]
at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:578) ~[selenium-remote-driver-4.37.0.jar:?]
at org.openqa.selenium.remote.RemoteWebDriver.startSession(RemoteWebDriver.java:246) ~[selenium-remote-driver-4.37.0.jar:?]
at org.openqa.selenium.remote.RemoteWebDriver.<init>(RemoteWebDriver.java:174) ~[selenium-remote-driver-4.37.0.jar:?]
at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:137) ~[selenium-firefox-driver-4.37.0.jar:?]
at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:132) ~[selenium-firefox-driver-4.37.0.jar:?]
at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:114) ~[selenium-firefox-driver-4.37.0.jar:?]
at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:109) ~[selenium-firefox-driver-4.37.0.jar:?]
at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:94) ~[selenium-firefox-driver-4.37.0.jar:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getWebDriverImpl(ExtensionSelenium.java:1175) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getWebDriver(ExtensionSelenium.java:968) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getWebDriver(ExtensionSelenium.java:936) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.internal.BuiltInSingleWebDriverProvider.getWebDriver(BuiltInSingleWebDriverProvider.java:63) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getWebDriverImpl(ExtensionSelenium.java:816) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getWebDriver(ExtensionSelenium.java:616) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getProxiedBrowser(ExtensionSelenium.java:777) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getProxiedBrowserByName(ExtensionSelenium.java:717) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getProxiedBrowserByName(ExtensionSelenium.java:693) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getProxiedBrowserByName(ExtensionSelenium.java:677) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.selenium.ExtensionSelenium.getProxiedBrowserByName(ExtensionSelenium.java:667) ~[selenium-release-15.41.0.zap:?]
at org.zaproxy.zap.extension.quickstart.launch.ExtensionQuickStartLaunch.lambda$launchBrowser$1(ExtensionQuickStartLaunch.java:221) [quickstart-release-52.zap:?]
at java.base/java.lang.Thread.run(Thread.java:1474) [?:?]
Caused by: java.io.UncheckedIOException: java.net.ConnectException
at org.openqa.selenium.remote.http.jdk.JdkHttpClient.execute0(JdkHttpClient.java:500) ~[?:?]
at org.openqa.selenium.remote.http.AddSeleniumUserAgent.lambda$apply$0(AddSeleniumUserAgent.java:42) ~[?:?]
at org.openqa.selenium.remote.http.Filter.lambda$andFinally$1(Filter.java:55) ~[?:?]
at org.openqa.selenium.remote.http.jdk.JdkHttpClient.lambda$executeAsync$2(JdkHttpClient.java:387) ~[?:?]
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:545) ~[?:?]
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:328) ~[?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1090) ~[?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:614) ~[?:?]
... 1 more
Caused by: java.net.ConnectException
at java.net.http/jdk.internal.net.http.HttpClientImpl.send(HttpClientImpl.java:923) ~[java.net.http:?]
at java.net.http/jdk.internal.net.http.HttpClientFacade.send(HttpClientFacade.java:133) ~[java.net.http:?]
at org.openqa.selenium.remote.http.jdk.JdkHttpClient.execute0(JdkHttpClient.java:459) ~[?:?]
at org.openqa.selenium.remote.http.AddSeleniumUserAgent.lambda$apply$0(AddSeleniumUserAgent.java:42) ~[?:?]
at org.openqa.selenium.remote.http.Filter.lambda$andFinally$1(Filter.java:55) ~[?:?]
at org.openqa.selenium.remote.http.jdk.JdkHttpClient.lambda$executeAsync$2(JdkHttpClient.java:387) ~[?:?]
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:545) ~[?:?]
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:328) ~[?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1090) ~[?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:614) ~[?:?]
... 1 more
Caused by: java.net.ConnectException
at java.net.http/jdk.internal.net.http.common.Utils.toConnectException(Utils.java:1070) ~[java.net.http:?]
at java.net.http/jdk.internal.net.http.PlainHttpConnection.connectAsync(PlainHttpConnection.java:223) ~[java.net.http:?]
at java.net.http/jdk.internal.net.http.PlainHttpConnection.checkRetryConnect(PlainHttpConnection.java:277) ~[java.net.http:?]
at java.net.http/jdk.internal.net.http.PlainHttpConnection.lambda$connectAsync$0(PlainHttpConnection.java:235) ~[java.net.http:?]
at java.base/java.util.concurrent.CompletableFuture.uniHandle(CompletableFuture.java:955) ~[?:?]
at java.base/java.util.concurrent.CompletableFuture$UniHandle.tryFire(CompletableFuture.java:932) ~[?:?]
at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:531) ~[?:?]
at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1794) ~[?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1090) ~[?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:614) ~[?:?]
... 1 more
Caused by: java.nio.channels.ClosedChannelException
at java.base/sun.nio.ch.SocketChannelImpl.ensureOpen(SocketChannelImpl.java:204) ~[?:?]
at java.base/sun.nio.ch.SocketChannelImpl.connect(SocketChannelImpl.java:942) ~[?:?]
at java.net.http/jdk.internal.net.http.PlainHttpConnection.connectAsync(PlainHttpConnection.java:211) ~[java.net.http:?]
at java.net.http/jdk.internal.net.http.PlainHttpConnection.checkRetryConnect(PlainHttpConnection.java:277) ~[java.net.http:?]
at java.net.http/jdk.internal.net.http.PlainHttpConnection.lambda$connectAsync$0(PlainHttpConnection.java:235) ~[java.net.http:?]
at java.base/java.util.concurrent.CompletableFuture.uniHandle(CompletableFuture.java:955) ~[?:?]
at java.base/java.util.concurrent.CompletableFuture$UniHandle.tryFire(CompletableFuture.java:932) ~[?:?]
at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:531) ~[?:?]
at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1794) ~[?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1090) ~[?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:614) ~[?:?]
... 1 more
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