We have a web application in .NET 4.5.x and have implemented the login with ADFS there. That was about 4 years ago and everything works as it should. I have been given the task of integrating ADFS into our new WebForms web application in .NET 4.6.2. However, the problem here is that after entering the user data, I am redirected to the start page of our web application, but I get the following error message with every user action (page change, editing data).