Übersicht
Attempting to access terminal remotely will result in a non-responsive server often falsely indicating the server is down.
Ursache
All servers use a 3-5-10 brute-force deterrent mechanism: three invalid logins in a five minute window results in a ten minute block. After ten minutes the block automatically expires and you may login again to the service.
Lösung
Use the right credentials, dummy! See KB: Zugriff auf das Terminal.