Reapply STS credentials for the Token Only (STS) logon policy (2016.3)
In 2016.3, changes were made to enable you to use the Token Only logon policy for multiple instances on a single server. As a result of this, after upgrading, you need to re-enter and re-save the User Name and Password for the STS Connection for each Service Desk Framework and Web Access application that is set to use the Token only logon policy in Configuration Center.