Difficulty getting sound to play on Psychopy all of a sudden

OS: Ubuntu 14.04.5
PsychoPy version: 1.85.3
**Standard Standalone? yes
**What are you trying to achieve?:
In Builder, I coded an experiment where a word stimuli and a beep is presented on each trial. To make the beep, I specified only the letter ‘A’ in the Sound section of the Sound stimuli component. It was working perfectly fine for a period of time, and then all of a sudden stopped working yesterday. I don’t know of any updates to the computer I’m using to run this experiment, and why it would all of a sudden stop playing a sound.
Thanks so much for your help with troubleshooting this!