Snap Thunderbird plays no sounds

I installed Thunderbird Mail 78.9.1 through Snap. I had previously been using a pre-compiled generic version which did not require installing. I copied the contents of my profile to the new installation and all is well except that it will not play the incoming mail alert; neither the custom one I always used (it has the correct path to the file) nor the default system sound. My previous installation would play either. It won’t play the calendar alert either. Someone on another forum advised that I might need to “grant the application access to the sound device”. I asked how to do that and I was directed to post my questions here at the Snapcraft forums. I do not know if that is what I need to do; I have no idea what the cause is.

Can you share the output of the following command?

snap connections thunderbird

Also, if you’re trying to use a custom sound file, it might be that the snap sandboxing doesn’t allow the application to read that file. Where is that file located on disk?

Link to the bug: