Error 553 when sending to mailing list

[The123king]

Hi, i've been experiencing Error 553 emails when trying to send to an online mailing list i am a member of.

The server response was: We're sorry, but we can't send your email.  Either the subject matter, a link, or an attachment potentially containsspam, or phishing or malware.  Please check or edit your message and try sending it again. (6-1-3-2) ID (63F6BC5E0A4DA9D6)

The email contains none of those, it's simply a plain HTML formatted email, with no links in it or attachments.

EDIT: It seems to affect ALL my traffic. First noticed when trying to send from webmail on a different network. Appears to be a BT server issue.

[DanielS]

Hi @The123king,

Thanks for getting in touch,

I am sorry to see that you're having problems sending to your mail list.

How many users are in the list? Have you tried breaking the list down into 2 or 3 lists to see if it sends that way?

Thanks
DanielS

[The123king]

It actually seems to affect ALL outgoing email.

[gg30340]

Are you a BT Broadband customer or paying for your email through a BT Premium email account?

Are you in the UK or abroad?

Are you using a web browser or an email client/app to access your emails?