If web - well, it sadly requires modern browser on relatively modern hardware - it has some performance problems currently in browsers, I'm not happy about that fact, I am considering improving it if the app catches enough interest.
If Android - please consider returning the app and getting your money back as long as you still can - I'm afraid I won't be able to solve it in quick fashion.
Does not work on my Galaxy Note 9 unfortunately(I granted the recording permission, but it can't pick up any sound). However, it works fine on desktop Firefox.
I think a try before you buy option would be useful.