ESP32 BLE does not communicate any more

Hi all,

I've been using some ESP32 chips. I program them from Arduino IDE and I can use the BLE interface to send/receive data. At some point the BLE stopped working on some of the devices and they all seem to have a similar issue, which is: I can still see the devices sending beacons and advertising themselves, I can pair, connect, get all the services and characteristics, but I can't receive/transmit actual data any more. I tried to reprogram the chips but it didn't work out.
Anyone had a similar issue or can suggest resources I can look at?

Thank you

Did you try loading some example sketches?

Actually no. I just tried to use the nRF Connect app on my phone and it looks like it receives the messages from the ESP32. So it's probably the phone at this point. But it can communicate with some other devices, that's why I'm confused.