Oops.....more Zigbee (waterleak) sensors going offline (and sometimes back ONline)

Months and months my four locations/hubs were working without any problems.
On one location a waterleak sensor went offline sometimes and back online. But on that location I have been changing the location of some Zigbee sensors.

Now four Zigbee aeotec sensors and an Ikea bulb are offline. Not a great problem but I am not near the hub so nothing I can do. Are Ikea bulbs supsect?
E.g. two Zigbee sensors are in my deepfreezer. One is online and his neighbour offline. I will never start understanding…
Lets be honest: With Z-wave I never ever had an offline device the last 8 years or so.
I will be there after some days and will do the 15 minutes off and on trick, but strange as I was having no problems whatsoever the last four months or so.

Edit: Solved now: I can enter the “advanced” and my offline Zigbee are Online now…pfff.

but now and then: error 500