Yeelight led ceiling Light is reset when switched off and on.

If I turn off the wall switch and after a while back on, then I can no longer access the yeelight ceiling Light via wifi and the lamp is reset and I have to reset the lamp via wifi.
What do I have to do so that the lights will not be reset and that they will keep their Wi-Fi?

Only on/off 5 times in a row will reset the lamp. It usually take 15 seconds even more to get back online after power cycle, you can push to refresh the device list to double check.