Exchange 2013 outlook 2007 we have 1 email that we gave full access permission to 3 employees. 1 employee when I add this second email address after a while it prevents outlook from sending mail, just sits in outbox. Soon as I unlink this second email the outbox will clear and the email sends. When I link it back up I an send a few after awhile outlook stops sending again.
In ECP I am going to the alt email and giving full access and send as permission.
In outlook I goto more settings, Advance open these additional mailbox's.