Facebook to the shared addresses adds something like fbclid + some special no. After entering this link, there is no page in php-fusion 404.
As the site excludes friendly links, everything is ok. The problem only occurs on the forum.
For example, I paste the link on facebook
http://pogoda-zachodniopomorskie.pl/website-members
Now, if someone wants to enter this link from facebook, then something like this is added to the link & fbclid = nr.id and the problem arises.