DTMF not recognized

Often, when on a call made by the RC app on a PC, and trying to make choices by pressing the number keys, some of the DTMF tones generated by the RingCentral app are not recognized. Perhaps their duration are too short, or the frequency is not quite right? This is a very annoying problem, and forces one to hang up and use a cell phone to make the call and enter the information using DTMF.