Many Internet Service Providers prevent users from connecting to port 25 on mail servers outside their network to reduce unwanted outgoing mail. This may prevent you from sending e-mail through a Paravel Solutions server.
Paravel Solutions provides outgoing mail (SMTP) service on port 26 as a workaround. To use this feature, configure your mail client to connect to the SMTP server on port 26 instead of port 25. Alternatively, you may use your Internet Service Provider's SMTP server.
If you are still having issues, please submit a Support Ticket: