I am seeing below screen when access to the AEM.
I checked the log the see follow error:
Doesn't anyone know how to fix it?
Have you modified the OOTB HTML library manager config? I would start looking there.
It seems other developer add the com.adobe.granite.ui.clientlibs.impl.HtmlLibraryManagerImpl.xml cause this error.
My AEM is working after I removed this file.
Correct config should be:
Did someone install a package and this started happening?
Java8 is a requirement for AEM 6.3. Make sure you are running java8 with AEM 6.3 else random bundles might break
Sounds like someone removed some internal clientlibs and files on which AEM is dependent.