[HELP]DTMF to PSTN number, using Zaptel (FXS) analog phone

Does anyone know something about DTMF tones through the FXS port on the TDM400 not reaching the called party??

Here’s an image with the explanation of the problem:

I’ve been searching a lot about the problem, but one of the only things that I found was setting relaxdtmf=yes, but no look.

Any ideas will be greatly appretiated…