No sound

The conference sound has disappeared. I checked the speaker, the test sound is not heard. The speakers are chosen correctly. Although the speakers work in other applications. I tried to turn on YouTube, everything is fine with the sound. When i connect headphones, there is sound in the headphones. Without headphones, there is no conference sound in the speakers. 

I tried reinstall the zoom, it didn't help. 

Please help,It’s like I’ve tried everything, I don’t understand what the problem is.