MinimServer unreachable since updates

[Animal]

Hi there,
About 2 days ago my QNAP TS-451+ (Intel x64) was updated to QTS 4.3.3.0095 and afterwards there was also an update for MinimServer (0.8.4.5 it says in the App Centre info) and since then MinimServer has become unusable/unreachable.
Even from the app-centre it can't reach the page on port 9790 anymore and of course also MinimWatch on PC is now grey and also my control-point (Lumin) says MinimServer is offline.
Have already checked FireWall-settings for Java on the PC but that's okay and of course that still wouldn't explain why Lumin also can't reach it anymore.
Luckily I'm in between streamers as I've sold one and am waiting for another to arrive but otherwise I would not be able to listen to my own music right now.
No idea what's causing this so help appreciated.
Regards, Louis.