lical426 Connecting the fax directly to the RG was a good test - it eliminates your house tel wiring as the problem. So, you have three things left - U-verse, the connecting cord, the fax. Does the fax have two jacks?? Try both jacks.
Can you try the fax on another line?? Can you try another fax on U-verse?? Try another connecting wire.
I think that fax over IP is a very special case - not this case. It means the fax generates IP. This case is fax over VOIP, Where the fax generates a tone (voice grade) the tone is modulated into the IP as if it were speech. This can have problems, too. But, the question is - Is it compatible with VOIP??
Your internet access speed should not affect your U-verse VOIP. It could affect Majick Jack VOIP. Your rate available could affect U-verse voice, but you should see that first in TV or internet. Hows your line?? Are you suddenly getting a lot of errors??
*The views and opinions expressed on this forum are purely my own. Any product claim, statistic, quote, or other representation about a product or service should be verified with the manufacturer, provider, or party.
While slim possibility that issue is with FAX port itself suspect issue is RG recently received new firm wire update, and an incompatibility now exists. Does your FAX have new updated drivers that can be downloaded,have you tried rebooting or performing factory reset of RG.