Sending of the message failed. An error occurred while sending mail. The mail server responded: <[email protected]> sender rejected. The email address you are sending as must match the email address you used to auth. Please check your SMTP settings. AUP#Out-1500. Please verify that your email address is correct in your account settings and try again.
Wšykne wótegrona (4)
This usually happens when a person has more than one email account and both are with the same email provider. If you have more than one email account, I first suggest you click to account settings and scroll down left side to Outgoing Servers SMTP and list the servers. There must be one for each account you have. Post back, and I'll try to help you in next steps.
In that case, the email id in full should be the same on both server settings. If you're unsure, please post screenshot of incoming server setting and outbound server setting. They both must show [email protected]
There seems to be a problem with sending from Spectrum POP accounts.
http://forums.mozillazine.org/viewtopic.php?f=39&t=3116013
I suggest you add the account as IMAP and see if it works. Use mail.twc.com, 993, SSL/TLS, normal password, email address for User Name, for the incoming, and the same for outgoing except port 587 and STARTTLS security.
https://www.spectrum.net/support/internet/mobile-email-setup