Audio is breaking up
The symptom is the audio from remote party is breaking up or audio from playing a file locally is breaking up.
It’s always recommended to check whether the problem exists with the latest git version of the libraries.
Check that no other application is using the devices. It is common to not be able to use sound device when the device is being used by other applications.
Check for dangling call in PBX. A dangling call is call that is left active in the PBX because previous (pjsua) application has terminated abruptly.
Check if audio is breaking up when playing file locally: Checking by playing a WAV file
Check if the breakup is coming from the sound device: Checking the quality of the sound device
Check if local audio is breaking up by looping back microphone signal to the speaker: Check by looping back microphone to speaker