Our Server is a Windows Server 2012 R2 Build 9600. The Kentico version we use is 8.2.49 and we tried also 8.2.50 but it changed nothing. We also have other sides on the server which running just fine. We also already tried to replace the Kentico files with a clean install but it has no effect... We guess there is some problem with the database because this is the only thing we not replaced yet as it is a big effort to do this.