Cheryl:

Which version of AR are you using?
Are you using MAPI or Direct as your send method?
Who is your email with? Telus, Shaw, Rogers, Google?
Are you using an Exchange server?

In general the answer to why it worked before and is not working now is because something changed.

This can be a difficult problem to solve over the forum as there are many different interrelated pieces to the problem that could be quick to fix if I was in front of it but may take a lot of back and forth discussion in this forum. Your Adagio consultant may be able to sort this out much faster by working with you directly.