I have created a new Mailbox, let's call it MB1. I have given full access and send as permissions to 5 colleagues. However when they try and send an email from the mailbox i.e. From: MB1@tvsscs.com they get a bounce back email from the mail server saying they don't have permission?
However, and this is the weird part, if they click on the 'From' button in a new email then select 'Other email address' and then manually search for MB1 in the Global Address List the can send the email fine.
Finally when they go to create another email and select 'From' and click on MB1@tvsscs.com from the drop down menu they get the permissions bounce back again. It only works when they manually select the mailbox from the Global Address List?
Any advice would be greatly appreciated.