So you're using Demon's mail server(s) to send mail that normally sends fine from your Demon ADSL using the SMTP authentication details Demon tell you to use?
Should work fine, unless your client's doing something odd. The only thing that might be worth trying is switching SSL on since it seems you're not already.
Should work fine, unless your client's doing something odd. The only thing that might be worth trying is switching SSL on since it seems you're not already.
Secure(SSL): No