Oculus Quest (one!) problem with Link

Hi all,
does anybody have a similar experience (or a hint)?
I was on holidays for 11 days, and right after that the Quest stopped working using Oculus Link. Before everything was fine, with MSFS and in general.
At first the headset and the PC app updated to V.30 (before the holidays it was V.29). Since then a connection via USB cable is impossible. I can’t register the headset in the app. The ‘OVRServer_x64.exe’ crashes repeatedly. The cable works perfectly, as it did before (I can see the memory content of the headset in the explorer).
I did all the ‘usual suspects’ stuff including repair or re-installation of the app several times.
The oculus helpdesk takes its time, so I hope that maybe there is someone around with a good idea. Thanx in advance.