Connection to zigbee motion detector no longer possible?

Hello,
I have a Homeassitant with CC2531 gateway via which I connect my devices.
The system ran for about 3 days and then stopped working.
The participant a Phillips and an Ikea motion detector are no longer accessible.
Although there is an IKEA radio socket in the next room that works as a router.

What could be the reason for this?

Zigbee & Phillips / Hue Motion sensor dropping?

See Philips Hue Motion Sensor Duds - #4 by bob.t