I attempted to login to the CF 10 administrator and got an error message: "An error occurred while executing the application. Please try again or contact the administrator."
Attempted to login with an incorrect password and got an error message: "Invalid User name or Password. Please try again."
The username and password were not changed.
I have two instances of CF Admin (Test and production) and both are inaccessible and throw the same error message (An error occurred...).
The applications are running.
I restarted the service successfully.
Update 20 was manually completed in July 2016. I was under the impression all further updates were set to "automatically" update, but I could be wrong. My first thought is that an update automatically occurred on April 25, 2017 (Update 23) which may have caused this problem.