How to move a mailbox to another server? (and retain functionality)

Hello!

I am trying to move our mailbox stores from one server (with server 03) to another server (08) and I am having a little difficulty. I can get the mailbox location moved, but then the user can only send e-mails, and will not receive any.

Any user trying to send to said user will receive a "System Undeliverable" message even tho the mailbox move was "Successful".