Confluence won't start after plugin update

[Paul Maina]

I updated a number of plugins and one of them froze Confluence. I have tried restarting the service a few times even in safe mode and even rebooted the server but no much luck. I am getting three errors that I have never seen before and Googling these is not yielding any fruits. Any assistance on these three errors?

First 2 are from the confluence log, last one is from catalina startup

2019-11-25 11:04:39,697 ERROR [localhost-startStop-1] [atlassian.confluence.event.ConfluenceEventDispatcher] run There was an exception thrown trying to dispatch event [ThemeConfigurationSavedEvent [saved=ThemeConfiguration [configurationSchemaVersion=6, intranetName=]]] from the invoker [SingleParameterMethodListenerInvoker{method=public void net.seibertmedia.confluence.plugins.theme.logosync.control.LogoSyncObserver.onThemeConfigurationSavedEvent(net.seibertmedia.confluence.plugins.theme.configuration.entity.ThemeConfigurationSavedEvent), listener=net.seibertmedia.confluence.plugins.theme.logosync.control.LogoSyncObserver@cb49802} (timed)]java.lang.RuntimeException: Unable to resolve owner of loading collection [[com.atlassian.confluence.core.ContentEntityObject.bodyContents#360453]] for second level caching. Listener: net.seibertmedia.confluence.plugins.theme.logosync.control.LogoSyncObserver event: net.seibertmedia.confluence.plugins.theme.configuration.entity.ThemeConfigurationSavedEvent

2019-11-25 11:04:55,941 ERROR [lifecycle:thread-1] [sal.confluence.lifecycle.TenantAwareLifecycleManager] triggerLifecycleAsTenant Unable to start component: com.atlassian.sal.confluence.lifecycle.MeasuringPluginUpgradeManager
com.atlassian.plugin.util.Assertions$NullArgumentException: Plugin key  should not be null!
        at com.atlassian.plugin.util.Assertions.notNull(Assertions.java:9)
        at com.atlassian.plugin.manager.ProductPluginAccessorBase.getPlugin(ProductPluginAccessorBase.java:146)
        at com.atlassian.plugin.manager.ForwardingPluginAccessor.getPlugin(ForwardingPluginAccessor.java:70)
        at com.atlassian.plugin.manager.EnabledModuleCachingPluginAccessor.getPlugin(EnabledModuleCachingPluginAccessor.java:39)
        at com.atlassian.plugin.manager.ForwardingPluginAccessor.getPlugin(ForwardingPluginAccessor.java:70)

2019-11-25 11:02:14,227 INFO [localhost-startStop-1] [com.atlassian.c onfluence.lifecycle] contextInitialized Starting Confluence 6.15.2 [b uild 8100 based on commit hash 4410012ac87e845516b70bc69b6f7a893eabaa 5a] - synchrony version 2.1.0-master-9d112c9d
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
Warning: validation was turned on but an org.xml.sax.ErrorHandler was not
set, which is probably not what is desired. Parser will use a default
ErrorHandler to print the first 10 errors. Please call
the 'setErrorHandler' method to fix this.
Error: URI=null Line=1: Document is invalid: no grammar found.
Error: URI=null Line=1: Document root element "atlassian-plugin", must match DOCTYPE root "null".

[Johan Soetens _Dumblefy_]

Hi Paul,

if it's a production instance, I'd recommend contacting Atlassian Support

Perhaps you could try clearing the plugin cache, have a look at Confluence Startup Problems Troubleshooting as well.

[Paul Maina]

Thanks for the tip, I had cleared out the cache folders as the first solution. However, I have managed to get it back up and running. The problem is that it took about 30 minutes to start up.

[Johan Soetens _Dumblefy_]

Glad you're up and running again, Paul. That sure is a long boot time, might be worth investigating it further.

Have a nice day.