We have 4 web servers, configured the same, that seemingly at random will start giving HTTP 500 errors. These are on separate Windows 2003 servers running IIS 6. All use the same ASP.NET API to pull an image from another “gateway” server. Sometimes this affects 2 or 3 of these web servers at one time and sometimes it affects all of them. It has been random with which ones it affects, I’ve found no pattern. Eventually, without any changes being made, the servers will start to work again. The servers affected all fail at once but they don’t all start working again at once.
We’ve tried rebooting the servers, restarting IIS, restoring the servers from weeks prior using multiple VEEAM replicas, none of this has fixed the issue while it’s happening. The last time this happened we had two of the 4 servers start giving this error, I disabled both of their NICs overnight, in the morning I enabled the NICs and one server started working again but the other was still giving the error. I disabled the NIC again on the one still giving the error and eventually hours later it began working again as well.
The log in IIS shows:“|42|800a0005|Invalid_procedure_call_or_argument”