Confluence fails to start after upgrading from version 8.5 to 9.2

[Hana]

Hello ,

Trying to upgrade confluence DC from 8.5.12LTS to 9.2.5 LTS on one node, but i got this error in the screen shot and nothing in the logs.

Any ideas plz , thanks in advance.

Regards,

[Charlie Misonne]

"Confluence had failed to start, but we're back up and running again".

What happens when you press the link below to go to the homepage?

From you screenshot I do not see any error. Just the message that there used to be an error which has been resolved now.

[Hana]

Hello ,

It redirects me to the same error page 

[Radek Dostál]

Which logs have you checked? Either confluence or catalina should contain something.

[Hana]

Hello ,

Thanks for your response i checked the catalina and i found these warnings : 

05-Jun-2025 14:50:30.217 WARNING [Catalina-utility-1] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesRmiTargets When running on Java 9 or later you need to add "--add-opens=java.rmi/sun.rmi.transport=ALL-UNNAMED" to the JVM command line arguments to enable RMI Target memory leak detection. Alternatively, you can suppress this warning by disabling RMI Target memory leak detection.
05-Jun-2025 14:50:30.217 WARNING [Catalina-utility-3] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [${confluence.context.path}#synchrony-proxy] appears to have started a thread named [logback-1] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
java.base/jdk.internal.misc.Unsafe.park(Native Method)

fyi : java version openjdk 21 

[Charlie Misonne]

the catalina log file will contains less information.

Please also check the atlassian-confluence.log file in the Confluence home directory.

[Ron Becker]

We have the same issue when upgrading to 9.2.5. Is there already known a solution for this issue?

The atlassian-confluence log says: 

2025-06-16 10:38:54,460 WARN [Catalina-utility-4] [confluence.util.profiling.DurationThresholdWarningTimingHelperFactory] logMessage Execution time for publishing event com.atlassian.plugin.event.events.PluginFrameworkShutdownEvent@30f13af5 took 13935 ms (warning threshold is 5000 ms)
2025-06-16 10:38:54,747 INFO [Catalina-utility-4] [com.atlassian.confluence.lifecycle] destroy Shutting down long running task service
2025-06-16 10:38:54,839 INFO [Catalina-utility-4] [com.atlassian.confluence.lifecycle] shutdownCacheManager Shutting down EhCache cache manager
2025-06-16 10:38:54,849 INFO [Catalina-utility-4] [com.atlassian.confluence.lifecycle] contextDestroyed Stopping Confluence
2025-06-16 10:38:54,876 WARN [Catalina-utility-4] [confluence.impl.webapp.ContextShutdownThreadListener] logAndInterrupt Non-daemon thread [pool-28-thread-1] is still alive, and may be blocking clean shutdown - interrupting