IIS disables Windows Authentication

Have a on premise system that has twice now in the past month disabled Windows Authentication within IIS.  This stops users from being able to login via LDAP authentication until enabled again.  Any suggestions on how to prevent this or what could be causing this?  

In my research it seems there have been other people with this issue and I would try the following:
 

• In the Event Viewer check to see if logging for IIS configuration is enabled.  The path to the logging is - Applications and services logs->Microsoft->Windows->IIS-Configuration->right click Operational->Enable logging. 
• Check to see if there is a group policy that is getting applied to the server causing this issue. 

I saw this issue occurred about 30 days ago from your previous post history. I have some further questions:
 

• Does this issue happen after a reboot or a simple iisreset command being issued in the command prompt?
• Is DocuWare the only application using IIS? Or is there other websites running? 

• We have since enabled IIS logging and will see what it reports next time it happens.  
• Customers IT does not believe or feel their is any group policy controlling this. 
• Doesn't seem to happen on a IIS reset.  
• Only thing on this server is DocuWare and only IIS website.    

Thanks for the response.  At this point we are just waiting to see when/if it happens again what the logs show..