Ok, I got a wierd problem. I just installed SBS 2011 (fresh install) and I went to everyones desktop and imported their PST (that were exported from the old exchange server). A couple of the people (for some strange reason) bcc and cc themselves when they send an email and they also cc a couple of other people in the office and the emails come back as underliverable. I watch them type the email and they type in the whole email address (not just the name).
I told them to type in just the name without the @ and the emails are delivered but not if they type in the whole email address for internal emails.
This video shows how to quickly and easily add an email signature for all users on Exchange 2016. The resulting signature is applied on a server level by Exchange Online.
The email signature template has been downloaded from: