Old light no longer responding

Hi All,
I’m using HUE Essentials to sync IKEA Trådfri lights, so i bought a premium account to be able to use Touchlink.
All that worked perfectly fine.

Problem i’m facing is that i have like 7 IKEA Trådfri lights in my kitchen working as expected, but now i tried to add another light to the Gateway - and 3 of the lights in the kitchen became unresponsive.
I have a HUE Controller on the wall that i use to turn lights off, but that one can only turn of 4 lights now - 3 are nog longer available.

In hue the lights says “Can not be reached”.

So each time im trying Touchlink to add a new light - a couple of lights get disconnected.
If i try to re-add them, others will get disconnected.

How can this be resolved?

Thank you

Nobody knows?!
This is so strange that it unsets itself.