Moved to ​https://docs.pjsip.org/en/latest/specific-guides/audio-troubleshooting/checks/dev_under_overflow.html

Check for audio underflows/overflows, by looking at the log (at log level 5) when the sound device is closed (for pjsua, this happens when the application exits). Look for line similar to this in the log:

 23:33:43.391 pasound.c Closing /dev/dsp: 0 underflow, 0 overflow