Sent emails bouncing back. 550 spam message received

[sjlsystems]

I am receiving the following message whatever type of email I am sending ie to one or multiple recipients, as a reply, with or without links or text only.

550 spam, or phishing or malware.  Please check or edit your message and try sending it again. (6-1-1-2) ID (613943C6107D06C8)

Incoming emails are fine.

This suddenly started happening yesterday some time between 1pm and 8pm. I have been using this email address for years. Other email addresses on my account do not appear to be affected

Tried BT Online Chat yesterday evening but they did not offer any help before signing off.

[JohnC2]

Hi @sjlsystems, welcome to the forum, and sorry you're getting this error.

Are these emails you are sending from your @btinternet.com address?
Are you trying to send the email using a client or via Webmail?

Cheers

John

[sjlsystems]

 Hi John

Thanks for replying

We are sending the emails from our @btinternet.com address.

If we try to send from Outlook they bounce back with the SPAM/Phishing message. If we send directly from the server they work OK.

We have 3 emails on the account. The other 2 emails work OK  sending from Outlook and get delivered with no problems.

Tricia 

[JohnC2]

Hi @sjlsystems, thanks for replying to me so quickly.

We'll need to look into this problem further for you. I've sent you a Private Message so you can get in touch with the Mod team and we'll be happy to help you get this fixed.

cheers

John