Chime keeps disconnecting

I have 2 chimes. They are located in 2 seperate rooms. Chime 1 keeps disconnecting almost every day for a few hours, then reconnects. Chime 2 ist stable. RSSI is around 50 for both. For testing I switched chime 1 and 2. Again chime 1 (now at the other location) is disconnecting and chime 2 is stable! So it’s clearly a problem of chime 1 and not related to the location or distance to the wifi router or anything like that. I can see many posts about disconnecting chimes but none with a solution. So what do I have to do to get this fixed?