Recently (last 3 months) we have had sporadic issues with our production IIS server (8.5.9600.16384) where websites are either running very slowly or they fail altogether. One of the websites in question is a classic ASP site, which we are hoping to phase out by the end of this year, but is still very much in use.
The most recent event was this past Sunday (4.28.2019) where the WAS error appeared for a specific application pool. The error would be repeated and then finally, the application pool would shut down. Each application pool would then follow in succession.
The event data shown is 5022 in the event log and the keyword is "classic."
In some cases, restarting IIS solves the problem, but in most cases it requires a total restart of the server. Yesterday, (4.28.2019) a full reboot was required.
Also, there seems to be a 7 day cycle to this issue as it has been occurring each Sunday. We've tried to see if there's a connection to the day of the week and any other activities, but can't find any.
The task scheduler for the server does reboots about 4 times each week because we felt that a preemptive reboot at around 1AM would clear any conditions that might cause a slowdown. It has helped, but we are still left with this issue which presumably is now restricted to Sundays.
Any ideas on how we can further debug and resolve this?
Thanks,
Bob