One user isn't saving in the database

I’m not sure if this is the right category to post this in, but as the name says, one user is not saving in the database.

He was on two days ago, made a character and everything was fine. He even logged out and logged back in that same day and everything was working.

Then yesterday he attempted to get on again and everything was gone. I looked in the users table in the database and all of his characters info was null. The only thing that showed was his identifier, but everything else like his names, phone number, inventory, etc was null. So he made a new character but as soon as he was done with the registration everything disappeared and he spawned as Michael and none of the info he put in was saved in the database. Also, I tried teleporting him to me, and teleporting to him but when I did the server said there is no player with that ID, so it thought he wasn’t online. And a lot of scripts don’t work for him, such as the HUD doesn’t show up, he can’t check or show his ID card, and other things don’t function for him.

I am not sure if this is an issue on the server side, or an issue on his end. Everything works perfectly fine for everybody else, so I assume it’s on his end. But, he did attempt logging into another server to test if it was my server or his PC, and for some reason the other server worked perfectly fine so I am really unsure which end is having issues.

I got him to clear his cache, that never worked, I got him to uninstall and reinstall FiveM and that also never worked.

Does anybody know what’s causing this, and how it can be fixed? Thanks in advance!

I don’t know why this happens is very strange.
I believe that the player has an issue on his/her pc because as you said everyone else is having a good time playing. I suggest to clear cache and reinstall GTA5 and then Fivem

Make sure that the player has steam or whatever game launcher they have gta 5 purchased on, up and loaded before they connect to the server.

don’t mean to necro a post, but the same is happening with me, i narrowed it down, if a player has a space in their steam name, it does not log them on my database, which is a huge problem, as this means their character and actions are not saved.
does anyone have a fix for this?
framework is QB, my Database is MySQL

did you figure this out?