5.1.1 Recipient address rejected: User unknown in virtual mailbox table

[HunterMedia]

5.1.1 Recipient address rejected: User unknown in virtual mailbox table

Hi,

I'm so not technical... but whenever I email this one person who happens to be quite important to my business I get this error.

I only get it when I email him or people within his company.
I don't get it with anyone else from any other country.

Please help,
regards,
Technical-challenged

[joximu]

well, on the way from your mail sw to the recipient there is one server which gives this answer - so find the server (normally it's also in the mailerdaemon-mail) and then you can focus on this server.