Here is a sample of the errors from the jenkins.err.log, Please note I am running this on a Windows system:
Jul 13, 2018 12:59:59 AM hudson.model.UpdateCenter$DownloadJob run
SEVERE: Failed to install JDK Tool
java.io.IOException: Downloaded file E:\Program Files (x86)\Jenkins\plugins\jdk-tool.jpi.tmp does not match expected SHA-1, expected 'K+QyfQDLMux19gZgQJSwtmwB2PY=', actual 'Ypx9ccYVxEg1XWqFBq2U+3RFh8w='
at hudson.model.UpdateCenter.verifyChecksums(UpdateCenter.java:1810)
at hudson.model.UpdateCenter.access$1100(UpdateCenter.java:149)
at hudson.model.UpdateCenter$InstallationJob.replace(UpdateCenter.java:1963)
at hudson.model.UpdateCenter$UpdateCenterConfiguration.install(UpdateCenter.java:1194)
at hudson.model.UpdateCenter$DownloadJob._run(UpdateCenter.java:1680)
at hudson.model.UpdateCenter$InstallationJob._run(UpdateCenter.java:1874)
at hudson.model.UpdateCenter$DownloadJob.run(UpdateCenter.java:1651)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at hudson.remoting.AtmostOneThreadExecutor$Worker.run(AtmostOneThreadExecutor.java:112)
at java.lang.Thread.run(Unknown Source)
Jul 13, 2018 12:59:59 AM hudson.model.UpdateCenter$DownloadJob run
INFO: Starting the installation of Script Security on behalf of admin
Jul 13, 2018 12:59:59 AM hudson.model.UpdateCenter$UpdateCenterConfiguration download
INFO: Downloading Script Security
Jul 13, 2018 12:59:59 AM hudson.model.UpdateCenter$DownloadJob run
SEVERE: Failed to install Script Security
java.io.IOException: Downloaded file E:\Program Files (x86)\Jenkins\plugins\script-security.jpi.tmp does not match expected SHA-1, expected '8Rmf3Rs4xMIJwTj+hUn92aoXE5E=', actual '+ys41rzhjFP1n8FaNxCSsaZy0P0='
at hudson.model.UpdateCenter.verifyChecksums(UpdateCenter.java:1810)
at hudson.model.UpdateCenter.access$1100(UpdateCenter.java:149)
at hudson.model.UpdateCenter$InstallationJob.replace(UpdateCenter.java:1963)
at hudson.model.UpdateCenter$UpdateCenterConfiguration.install(UpdateCenter.java:1194)
at hudson.model.UpdateCenter$DownloadJob._run(UpdateCenter.java:1680)
at hudson.model.UpdateCenter$InstallationJob._run(UpdateCenter.java:1874)
at hudson.model.UpdateCenter$DownloadJob.run(UpdateCenter.java:1651)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at hudson.remoting.AtmostOneThreadExecutor$Worker.run(AtmostOneThreadExecutor.java:112)
at java.lang.Thread.run(Unknown Source)