Can't Access Confluence Through Mobile
Platform notice: Server and Data Center only. This article only applies to Atlassian products on the Server and Data Center platforms.
Support for Server* products ended on February 15th 2024. If you are running a Server product, you can visit the Atlassian Server end of support announcement to review your migration options.
*Except Fisheye and Crucible
Problem
You are unable to access Confluence through mobile.
The following appears in the atlassian-confluence.log
java.lang.IllegalStateException: Request-local WebResourceAssembler has already been initialised
at com.atlassian.plugin.webresource.assembler.DefaultPageBuilderService.seed(DefaultPageBuilderService.java:48)
Stack Trace:[hide]
java.lang.IllegalStateException: Request-local WebResourceAssembler has already been initialised at com.atlassian.plugin.webresource.assembler.DefaultPageBuilderService.seed(DefaultPageBuilderService.java:48) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at com.atlassian.plugin.util.ContextClassLoaderSettingInvocationHandler.invoke(ContextClassLoaderSettingInvocationHandler.java:26) at com.sun.proxy.$Proxy400.seed(Unknown Source) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:302) at org.eclipse.gemini.blueprint.service.importer.support.internal.aop.ServiceInvoker.doInvoke(ServiceInvoker.java:56) at 
Please note that this error is very similar to another issue which also causes Confluence to become inaccessible on mobile. If the below solution does not work for you, please also check: Can't Access Confluence Through Mobile or Saving is not Possible After Upgrade
Cause
This is caused by the server base URL not matching the current URL.
Resolution
The resolution is to change the server base URL or access it by the one already set there. Please see Configuring the Server Base URL.