Too much connections to the server

I got a strange message on my Self Service portal.

Die erlaubte maximale Anzahl an Verbindungen zum Server wurde erreicht. Bitte versuchen Sie es in 6.0 Stunden erneut.

Where do this come from and what to do to prevent such thing?


Very strange message. The problem was a wrong configured mail server. I changed from localhost to the IP address of the relay host. Then it worked again.