To get detailed error description for the "Sorry, something went wrong" message click "TECHNICAL DETAILS" link.
You'll see "Correlation ID". Copy it.
Run in any SharePoint server following command in SharePoint Management Shell (replace <GUID> with copied Correlation ID):
Merge-SPlogfile –Path c:\log.log –Correlation <GUID>
e.g. (Merge-SPlogfile –Path c:\log.log –Correlation b894159c-18a0-d024-0161-595dc334620c)
By the path c:\log.log, you'll find log.log file with detailed error description.
If the command returned no results:
WARNING: Cmdlet did not return any records in the log file. Check your time range or filters.
Check that logging is configured in Central Administration -> Monitoring -> Configure Diagnostic Logging.
If nothing is selcted there, check "All Categories" and Save.
Reproduce the error, and get details by new Correlation ID.