Our SP 2013 farm was patched with windows updates recently and one of our web front end servers is displaying a blank page. We've disabled logins to this server now so all users are logging into the other web front end.
AAM was checked, Reset IIS, Cleared SP config cache, Added dword value 1 to loaderoptimization and rebooted
Current farm is Two WFEs Two App One DB
Edit: found this error as well on the WFE: An update conflict has occurred, and you must re-try this action. The object SPWebService was updated by DOMAIN\farmacc, in the OWSTIMER (15452) process, on machine WFE2.