Reason
Your mail system has reached the connection limit. Your system tries to establish more connections to our mail system than are allowed for the respective IP address.
Solution
If you get a temporary error as soon as you want to establish another connection, your system has to wait until one of your existing connections has been terminated and thus a new connection can be established again. Your mail system should be able to handle this common practice automatically.
Note that the connection limit is configured per Mail Exchange Server. You have to expect that this value differs per system and can be changed at anytime. Exceptions or individual limit changes cannot be made.
See also: General information on our error messages.