Connection to https://webapis-discovery.appspot.com refused

[kaluva via StackOverflow]

I'm learning google clound endpoints. I followed the instructions given in below link:

https://cloud.google.com/appengine/docs/java/endpoints/getstarted/backend/hello_world

But i'm not able to launch the URL suggested in the tutorial once server started:

http://localhost:8080/_ah/api/explorer

Appengine Server started successfully but when i hit the URL it is getting redirected to:

http://apis-explorer.appspot.com/apis-explorer/?base=http://localhost:8080/_ah/api#p/

and getting

Connection to https://webapis-discovery.appspot.com refused

Below is the log for the same:

[INFO] SEVERE: javax.servlet.ServletContext log: unavailable
[INFO] java.io.IOException: Could not fetch URL: https://webapis-discovery.appspot.com/_ah/api/static/proxy.html, error: Received exception executing
http method GET against URL https://webapis-discovery.appspot.com/_ah/api/static/proxy.html: Connection to https://webapis-discovery.appspot.com refus
ed
[INFO]  at com.google.appengine.api.urlfetch.URLFetchServiceImpl.convertApplicationException(URLFetchServiceImpl.java:138)
[INFO]  at com.google.appengine.api.urlfetch.URLFetchServiceImpl.fetch(URLFetchServiceImpl.java:45)
[INFO]  at com.google.apphosting.utils.security.urlfetch.URLFetchServiceStreamHandler$Connection.fetchResponse(URLFetchServiceStreamHandler.java:417)
[INFO]  at com.google.apphosting.utils.security.urlfetch.URLFetchServiceStreamHandler$Connection.getInputStream(URLFetchServiceStreamHandler.java:296)

[INFO]  at com.google.apphosting.utils.security.urlfetch.URLFetchServiceStreamHandler$Connection.getResponseCode(URLFetchServiceStreamHandler.java:149
)
[INFO]  at com.google.appengine.repackaged.com.google.api.client.http.javanet.NetHttpResponse.<init>(NetHttpResponse.java:36)
[INFO]  at com.google.appengine.repackaged.com.google.api.client.http.javanet.NetHttpRequest.execute(NetHttpRequest.java:94)
[INFO]  at com.google.appengine.repackaged.com.google.api.client.http.HttpRequest.execute(HttpRequest.java:965)
[INFO]  at com.google.api.server.spi.tools.devserver.StaticServlet.getStaticContent(StaticServlet.java:58)
[INFO]  at com.google.api.server.spi.tools.devserver.StaticServlet.cacheContent(StaticServlet.java:50)
[INFO]  at com.google.api.server.spi.tools.devserver.StaticServlet.init(StaticServlet.java:43)
[INFO]  at javax.servlet.GenericServlet.init(GenericServlet.java:212)
[INFO]  at org.mortbay.jetty.servlet.ServletHolder.initServlet(ServletHolder.java:440)
[INFO]  at org.mortbay.jetty.servlet.ServletHolder.getServlet(ServletHolder.java:339)
[INFO]  at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
[INFO]  at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
[INFO]  at com.google.appengine.api.socket.dev.DevSocketFilter.doFilter(DevSocketFilter.java:74)
[INFO]  at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
[INFO]  at com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:127)
[INFO]  at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
[INFO]  at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34)
[INFO]  at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
[INFO]  at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:63)
[INFO]  at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
[INFO]  at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
[INFO]  at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
[INFO]  at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:125)
[INFO]  at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
[INFO]  at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectRequest(DevAppServerModulesFilter.java:366)
[INFO]  at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectModuleRequest(DevAppServerModulesFilter.java:349)
[INFO]  at com.google.appengine.tools.development.DevAppServerModulesFilter.doFilter(DevAppServerModulesFilter.java:116)
[INFO]  at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
[INFO]  at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
[INFO]  at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
[INFO]  at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
[INFO]  at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
[INFO]  at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
[INFO]  at com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:98)
[INFO]  at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
[INFO]  at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:491)
[INFO]  at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
[INFO]  at org.mortbay.jetty.Server.handle(Server.java:326)
[INFO]  at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
[INFO]  at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:923)
[INFO]  at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:547)
[INFO]  at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
[INFO]  at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
[INFO]  at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
[INFO]  at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
[INFO]
[INFO] Oct 15, 2014 5:38:00 PM com.google.apphosting.utils.jetty.JettyLogger warn
[INFO] WARNING: /_ah/api/static/proxy.html: java.io.IOException: Could not fetch URL: https://webapis-discovery.appspot.com/_ah/api/static/proxy.html,
 error: Received exception executing http method GET against URL https://webapis-discovery.appspot.com/_ah/api/static/proxy.html: Connection to https://webapis-discovery.appspot.com refused

I'm behind proxy but even if i set the PROXY settings from cmd prompt or in eclipse, getting same error.

Can any one able to launch the URL successfully by following the above tutorial? Any changes to be done to make this working? Please suggest.

Please DO NOT REPLY directly to this email but go to StackOverflow:
http://stackoverflow.com/questions/26382466/connection-to-https-webapis-discovery-appspot-com-refused

[kaluva via StackOverflow]

Another user,@saurabh, also asked same question. Looks like there is no accepted solution yet:

Google Cloud Endpoints : Not able to open http://localhost:8080/_ah/api/explorer behind a proxy network