Cant create mailbox

My company admin is trying to create a mailbox for my user account, however we keep getting the error that Can't create MailID.

We've had a couple of goes creating our organisation account and it looks like we might have some legacy information left on one or more of your servers. We have created multiple user accounts all assigned to the same organisation as we have had different problems with each one.

This is really important for me to be able to receive email as the rest of the organisation has moved across other than me.

Thanks
NH