Windows Fax & Scan

I have a physician office that sends/receives tons of faxes daily and a couple of days ago the fax service started continually failing. I deleted everything out the fax queue folder and now it stays on. However, now every time it tries to send/receive a fax, the fax monitor shows "The fax can't be received because of an unexpected error." It's running Server 2012 R2. What can I do to fix this??