Recently I started to see my CC2531 USB becoming unresponsive. And indeed, in the logs I see:
Zigbee2MQTT:error 2020-10-16 14:21:34: Error while starting zigbee-herdsman
Zigbee2MQTT:error 2020-10-16 14:21:34: Failed to start zigbee
Zigbee2MQTT:error 2020-10-16 14:21:34: Exiting…
Zigbee2MQTT:error 2020-10-16 14:21:34: Error: Failed to connect to the adapter (Error: SRSP - SYS - ping after 6000ms)
at ZStackAdapter. (/zigbee2mqtt-1.15.0/node_modules/zigbee-herdsman/dist/adapter/z-stack/adapter/zStackAdapter.js:92:31)
at Generator.throw ()
at rejected (/zigbee2mqtt-1.15.0/node_modules/zigbee-herdsman/dist/adapter/z-stack/adapter/zStackAdapter.js:25:65)
However, this is not permanent. If I reinsert the USB stick in my RPi, it starts to work. After a while, it becomes unresponsive again.
Any ideas what might be wrong ?