I am currently migration the Jabber Server to a new environment, complete with new IP address. The DNS changes are published, but it might take up to 12 hours until the changes are globally visible. During this time the Jabber Server will be somewhat in a wobbly state. You might experience disconnections, not able to connect at all or offline friends (that are actually online).
There is nothing we can do but wait – DNS is not the fasted propagating information system out there.
UPDATE: Please be SURE you did not enter any server name or ip address. The Server is now running on jabber.alpha-labs.net. If you just entered your jabber-id like email@example.com, DNS SRV records will automagically point you to jabber.alpha-labs.net. If you, however, entered alpha-labs.net as servername, you will not be able to connect.