Zigbee network crash

Hello
I m working with deconz on a rpi4 with jeedom, with a conbee2.I have a zigbee network working since more than 2 years without issue and approximatively 70 sensor/switch.
2 weeks ago during the night all the network collapse.
I try to reload the network on my conbee2 key but no improvement. I have a second conbee2 on a pc, I do the same but again no improvement.
I repaired manually 2 or 3 equipments, but before to do it with all, I would like to know if you have any idea how it s possible to have this kind of crash?

Last point, on the day before I saw my tradfri plug pulsing continuously, do you think it s should be link to my crash?
Thanks