Zerotier Goes offline and doesnt come back on Kubuntu/Ubuntu

Hi there,
not much of a network guy. but i have an old machine using as a backup place for everything with Kubuntu LTS running on it. about an week, after system update, i think zerotier also updated. and connection went offline.
did a system restart, it connected. and never thought about it. until it keeps going offline. sometime even after restarting, it doenst connect.
it can still leave and join the zerotier netweork
but stays Offline.
i have tried just restarting the systemctl service. it doesnt help.
any help would be nice. since right now i can only maintain my stuff mostly from the same network. and cant always restart the whole thing.

update:
Still havent been able to keep the connection with the zerotier network. it does connect occasionally after restart. will work for a bit period. then disconnects and never connects again.
restarting doesnt always help. some after restart results offline still.
even when its working. it will still show on zerotier network that it was disconnected x min ago. exactly the time i had the system restart .
i have done a full reinstall, nothing
help please