Some ISP's have a policy of blocking port 25 which is used
for SMTP. The following can be done to test this:
1. In Windows go to the Start Menu then select 'Run...'.
2. Type: telnet domain.com 25 (where domain.com is
replaced with your domain name)
You should see an ms-dos window popup with an Exim
welcome message (the software we use for email on
servers). If there is no message it is possible that your ISP
blocks port 25.
If your ISP does block port 25 we can bypass this by allowing
the use of another port for SMTP (usually port 26). To see if
your server is already setup for this follow the same steps
again and enter 'telnet domain.com 26' (without quotes). If
still no welcome message please open a support ticket and
we will open port 26 on your server or look into the cause of
the problem.
Following this you will be required to change the port for
SMTP in your email software. Please consult the
documentation that came with the software to do this.