Outlook Anywhere Connection Failure only for Mac Outlook users after 11.3 upgrade to 11.5.2

OK. Did you use the Exchange iApp to deploy, and if you did, which version did you use? I assume you are using APM since this is tagged as such...have you tried checking the access policy and SSO debug logs on BIG-IP for errors? You'll need to set those two logs to "Debug" from the System>Logs>Configuration>Options, then tail /var/log/apm while attempting to log in from a Mac.