We have an issue which occurs intermittently on one of our test environment. The issue is mostly observed when a deployment is carried out but the peculiar behavior about the issue is the post deployment sanity test completes with out any issues however when the system is accessed bit later it results in a server error.
The primary website is an onprem Sharepoint 2013. We have two asp.net MVC web application which are accessed through a custom webpart in a iframe. The assembly (Microsoft.IdentityModel.Extensions) is used as part of the asp.net application for authentication. When the user clicks on the menu item it open one of these asp.net web application opens however in the error scenario it presents us the the server error.
We do an iisreset which resolve the issue immediately without any change to the config, IIS settings or any type of code change. My question is how do we stop from getting the exception at first place. At the moment it occurs only on one of the test environment and not observed on production. Is something to do with IIS not loading the assembly what could be the possible trigger or any patch or a known issue?