Re^7: e-mail fails with address that is not a fully qualified domain

[Anonymous Monk]

Can anyone suggest how I can make these e-mails actually arrive and/or find out what is happening to them?

Contact the administrator

When a SMPT server tells you, you've authenticated, your mail has been sent ... your only choice is to believe it

[merrymonk]

I can see your very reasonable point?
I see you suggest I talk to the administrator but I am not sure who this is this particular case.
I get my broadband services from Virgin Media but use an e-mail account from bt (British Telecoms). Therefore does this make it bt that I should talk to? Using Thunderbird with the from address I am using does work OK.

[mr_mischief]

You would need to talk to the administrator of the server to which you submitted the mail for sending. If it is then forwarded to another server for delivery, you'd want to speak to that administrator as well.

A big part of software development is understanding with what your programs interact. In this case, not only do you have a human user but also the SMTP protocol and mail servers. I suggest becoming more familiar with how SMTP email works. The domain knowledge is invaluable to someone writing code for the domain.