teamviewer host connection impossible after system time change

rejuce

I have this situation:

a debian 10 linux system running: most of the time the system is offline. hereby the system time is synchrnoised with another local device. so the other device sends its time, our appication processes that and set the linux sys time with that.

after the sys time was change in that way, teamviewer host still shows its reachable. but no matter which client tries to connect to it, it is stuck in "connectin..." indefinitely

what can that be?