RM options do not save

Hello!
Thank you for such a great plugin. I use RankMath on all my pages.
Now, I am creating a new one and something unusual occurred.
Please, check this recording: https://recordit.co/CRcUrOCWWe
As you can notice all plugins except RM was deactivated. And here is the clue -> when I tried to change options and save them…they refuse to be saved:)
Really do not know what is wrong as all plugins are deactivated.
I provide credentials to FTP and WordPress site so you can check this on your own.
I think this error do not consider only me.
Hope you would help and indicate where the bug is hidden.
Regards,
Greg