No problem, I can understand you, and I also feel sorry because I don't always have the right answer.
But the strange thing is, I never had such issues, on both of my current PCs (one higher end machine with nVidia card, and one laptop with realtively poor AMD Radeon mobile graphics, both with Windows 7 ).
It only happened a few times that the game was suddenly stuttering after the updates, most likely because some settings in the config file have been changed or became invalid with the update. The solution here was to delete the config file, and readjust some settings carefully, that's it.
But never connection problems like yours. If there was a connection problem, then one time because the master server was unavailable, but this is not the case actually (luckily for all the others).
I really presume that your security programs like avast, fsecure, defender, whatever, except Avira Antivirus Pro (I know it works with Avira, because I use that), or perhaps firewalls have blocked Maniaplanet.
Why? Because all major updates install a new ManiaPlanet.exe, which is normally recognized as potential risk.
So if some people ignore or forget the firewall message ("Maniaplanet wants to access... allow or not?") that appears in the background (easily overseen in fullscreen mode), then some features will be blocked.
Second possible issue, at the restart of the game, if it is not started with Admin rights, it can't configure the system adequately, and perhaps some things don't work anymore here.
You know, I'm also very interested to find or to get to know the solution.
And I hope you, or Nadeo, find it very soon!
Until then, please double check your configuration.
If possible, try another PC in the same network, or try your PC in a different network, to see if there is a different behavior.
