All right, I'll send all the information about this address. Thank you for your help!

Yes i delete all caches in Dashboard > Forums > Dashboard admin page . Capture-d’écran-2018-09-18-à-15.13.08.png

I followed your steps and then tried to create my subject and I have this error that appeared: [Subquery returns more than 1 row]SELECT `slug` FROM ap...

Thank you, with this solution I was able to delete my topic but I still have this problem when I recreate a topic and click on it to post a message no...

After i search my post it does not appear in the moderation and i have this problem : When I wanted to search for my post I have this error that appea...

Do you have a solution to solve this problem please ?

I tried the link solutions you sent me but it still doesn't work

I put my site in debug mode and here is what it shows me: Erreur de la base de données WordPress :</strong> [Can't find FULLTEXT index matc...

I did several tests and I saw that it was when I syncronized all users that this problem happened. I have imported into a new site all my without the ...

I have disabled all plugins and also change the theme and the problem persists... This is my website :/p>

I did everything you asked but the problem persists... The problem is that on the registration when I log in I don't have a problem.