All was well until yesterday when I could not send emails USING MY OWN DOMAIN NAME. I do not use Virgin Media/NTL email addresses, I use my own email address ,example, email@example.com .As I say until yesterday worked fine sending using the SMTP
smtp.ntlworld.com my account email address firstname.lastname@example.org and a password for SMTP. I have changed nothing and therefore were would the problem lie ??