Unable to receive faxes when in DRPD Mode on 2335dn Printer

Hello:

I am unable to receive faxes on my 2335dn all-in-one when it is setup in DRPD mode.   I can test the lines and I do get a fax tone on the fax line and the regular phone on that line.   The fax line rings 3 times goes to receiving, but never puts through a fax.  I have reset the DRPD mode and can detect the fax line each time.