Can not send E-mail via Webmail -Error code SMTP 550, sender domain rejected

[#1]

For the last 48hrs can not send any emails from IMAP or direct from webmail.plus.net.

Using legacy totalise email; xxxx@totalise.co.uk.

Error message: SMPT 550, Fialed to set sender xxxx@totalise.co.uk, sender domain rejected. 

Is this a possible security certificate issue?

any help much appreciated.

[#2]

 A warm welcome to the forums.

Sorry that this post seems to have been missed.  Do you still have a problem?

[#3]

Sender Domain Rejected (black listed by local policy)

This issue can report as server error 550. It typically arises where a user's email address has been abused for the purposes of sending spam emails. It has nothing to do with server settings etc.

This requires intervention by staff to determine the cause of the problem and to issue advice to check your system for viruses and malware. Only after your system(s) have been affirmed to be clean can the black listing be lifted. As a precaution, you should change the password on the affected email address.

Add your details to this thread - Cannot Send Emails and send a PM to @Leanne_T

[#4]

Hi Thanks for the info. Much aporeciated