Call problem

When I make a call with someone who is using discord on a phone suddenly he stops talking and his photo is marked in green, as if he were speaking, the other has to disconnect and reconnect to fix it. It's quite annoying and it has happened to me for months.

Here is a photo of how the user looks in case it was not understood well:

it stays like this all the time but you don't hear anything.

How can it be fixed?