i have looked at similar posts and tried their solutions, i used to get user name or password not recognised but now I get sender address is rejected by server.
Make sure your outgoing settings are correct.
Use the advice in this post here to get to the SMTP settings.
Make sure you use the following settings EXACTLY
Server: smtp.virginmedia.comPort: 465SSL enabled (Slider should be showing green)Username: Your FULL email addressPassword: - speaks for itself reallyAuthentication type: Password
Note: If you do not have username and password entered the Authentication type ends up as none. Which would lead to the error you are experiencing.
Only use Helpful answer if your problems been solved.