I am currently running three environments (development, acceptance, production) of ArcGIS Enterprise 10.6.1 on Windows 2012 servers (Portal and Server are federated) and I am experiencing an issue (only on the acceptance environment) where all of our web services within ArcGIS Server are shown with a status of "Stopping".
In the ArcGIS Server logs, two big error codes appear after each attempt to restart the ArcGIS Server windows service. The error codes are 6550 (failed to start the server machine) and 7365 (error while starting AppServer). I began my troubleshooting by restarting the ArcGIS Server windows service. After that didn't fix the issue, I rebooted the entire server (didn't fix the issue). After that, I went through and checked multiple things including verifying that the windows account running ArcGIS Server has the correct folder permissions set, verifying that I have a valid licenses to run ArcGIS Server, verifying that the acceptance environment is configured the same as the development and production environments, and verifying that the acceptance environment has the same ArcGIS Enterprise patches installed as the other environments.
I will note that this behavior occurred after some recent windows patches were installed on that server. When comparing the timestamp of the errors appearing in the ArcGIS Server logs to the timestamp of the installation of the windows patches on the acceptance server, they are very similar (same day). This leads me to believe that the recent windows patches had some affect on ArcGIS Server. The odd thing is that the same windows patches were installed on the development and production environments with no issues arising after installation. I contacted ESRI support and all they can tell me to do is to attempt to uninstall the windows patches to see if it corrects the issues or uninstall/reinstall ArcGIS Server in that environment. I would rather not have to uninstall/reinstall ArcGIS Server due to possible issues that might arise from our federation with Portal. This is the first time I have ever experienced this behavior in any version of ArcGIS Enterprise. Does anyone have any other suggestions for things I can try?