We are running a Federated environment of ArcGIS Enterprise 11.1 (all patches applied), and just recently started having issues with losing connections to ArcGIS Server, Portal, and map services. It is noticed when map services do not load in a web application, then cannot open login pages to any of the above services. Everything is back up as normal within approximately twenty minutes.
I have checked the Windows Server system logs, the ArcGIS Server statistics reports, and nothing is out of the ordinary. It happens at random times, random intervals.
Has anyone else experienced such a thing?