Windows 7 Fax & Scan Not Sending Complete Fax?

I'm running Windows 7 and have activated the Windows Fax & Scan software. The modem Verizon USB760 is our fax modem. When the software was initially activated, outgoing faxes were sent fine. Recently, it's stopped working completely. Only the coverpage is sent, the fax job fails and retries as many times as I have it configured or until I delete the fax job. I've tried typing directly into the section for page 2 of the fax, and I've tried attaching pdf or txt files with the same incomplete result. I can view the complete fax in the outbound box.