PSN account problem | PS4 | AC4 Black Flag Multiplayer?

I've had a problem since Monday.

I've been playing the multiplayer mode of Assassins Creed IV Black Flag for a while and it always worked. It was the same on Monday evening (September 7th, 2020).

Just before 11 p.m., however, someone in our house allowed himself a little fun and kept plugging in and unplugging the console's LAN cable.

This of course led to the fact that I kept getting out of the online multiplayer area and coming back in again, so I went online there (also in quick succession).

That worked a couple of times, until suddenly I could no longer enter the multiplayer interface / multiplayer area even with the LAN cable permanently plugged in. It has stayed that way to this day!

My guess was that this quick change may have caused some kind of lock / block, which now denies me access to the multiplayer mode.

Maybe the system or the algorithm thought I was a bot or wanted to damage the server?

Why do I come to that? It is still possible to enter the multiplayer area as usual with the same Playstation and the same Internet connection, just with other PSN accounts (such as that of a friend). The following message only comes up when I start the game under my PSN account and want to enter the multiplayer mode:

"The Ubisoft services are currently not available. Please try again later. The restricted mode is now active, you can't use any features that require a connection to the Ubisoft services."

AND NO, IT'S NOT UP TO THE SERVER!

I have already contacted Ubisoft (as the developer of the game), but they said that they did not have the ability to block players and sent me to Sony or Playstation.

As I said, the message only appears with this PSN account. Not with other accounts.

A telephone conversation with a member of staff showed me that my PSN account is not blocked. I can also register with PSN as normal and use the other online features!

Just don't enter the multiplayer mode of this game (AC4 BLACK FLAG) anymore.

Maybe one of you knows something about it?!

I would be really happy about it.

So here are a few things I would try:

Hit the person who did this (irony).

2. Tried to delete the game and reinstall it?

3. Initialize Ps4 - once had blue light of death and initialized my Ps4 (deleted everything) then logged back into my account and downloaded my games and everything was fine again (but only do this in extreme cases)

I hope one of the options can help you (yes, the first one too)