"I'm sorry to have to inform you that your message could not be delivered" and user that does not exist - strange proble

[adamdudzik]

Hello, i have a strange problem.

Every time I send an email to all@mycompany i receive a one return message:

"This is the mail system at host mycompany.

I'm sorry to have to inform you that your message could not be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can delete your own text from the attached returned message.

The mail system user@mycompany"


This account: user@mycompany was on the server but has been deleted.

As part of the test, I set up a second account with the same login and deleted it again, but it did not change anything

how to fix it?