If you receive delivery failure messages for emails you did not send, there are two common causes.
Your mailbox may have been compromised, or a spammer may have spoofed your email address.
Change the Mailbox Password
Change the mailbox password immediately.
This is the safest first step because it stops anyone from logging in if the password has been compromised.
Use a strong password that is not used anywhere else.
Contact Support
Open a support ticket and tell us what has happened.
We can check the server logs to see whether the messages were sent through your mailbox or whether your address was spoofed.
If the Mailbox Was Compromised
If the mailbox was used to send spam:
- Change the mailbox password.
- Check for unknown forwarding rules or filters.
- Scan any devices that access the mailbox.
- Make sure the same password is not used anywhere else.
- Contact us so we can check whether any further action is needed.
If the Address Was Spoofed
Spoofing means a spammer sent email using your address as the fake return address.
In that case, the spam did not necessarily come from your mailbox or our server.
Unfortunately, you may still receive delivery failures because the failed messages are returned to the address shown in the email headers.
Why We Need the Headers
The email headers help show where a message really came from.
If you contact support, include one of the delivery failure messages with the full headers if possible.
If you are not sure how to get the headers, send us the message you received and we will advise you.