In the past two days, I've observed that certain members' profile pages have become inaccessible throwing 404 errors. An example is this user (link), who has been highly engaged in the community with hundreds of posts; however, attempting to access their profile now leads to a 404 page. I am currently using WPforo 2.17 and haven't made any changes to plugins. While I have upgraded to WordPress 6.4.1 and PHP version 8.1, I am skeptical that these updates would be the cause of the broken member profile URLs. Has anyone else encountered a similar problem, and if so, do you know of any solutions?
The link you provided is correctly returning 404, the profiles are at
His profile is somehow REDIRECTED and results a 404.
Maybe you are using some other plugin for profiles. The wpForo profiles are at /participants as i told you.
Try to edit the maliblu user and change the Nickname to something elese, e.g. to malibluuu. Save it, got to Dashboard > wpForo > Overview, scroll down, find the [Delete all caches] button and click it, then check then find and check the new URL of this user profile page.