I keep getting the above I run the check and get the verification code and reactivate but then shortly after I run a test send even though the test is received at the client the SMTP reports 3 consecutive errors and stops.
We will have a look and try to provide some more detail.
EDIT:
Your mail server is not responding, so this would indicate that either the SMTP host name is wrong, or alternatively the SMTP server is blocking our connections. If you haven’t changed anything I suspect the latter is true, if you call up your host they should be able to confirm this.