Mijia g1 essential voice issue

Hello,
I have a problem with my mijia g1. After some time of usage the vacuum cleaner suddenly stopped to speak. I checked the app and everything is activated (voice button is on). The robot simply doesn’t speak. It speaks only if I change the volume, just to say that the volume was changed.

I tried a factory reset: the robot started again to speaks for a while and then silence again.

Anyone can help me? Anyone experienced the same issues?

I have the firmware 2.0.8.6139 and I'm located...

Mijia g1 essential voice issue