Anonyme Ban not working

Where do you call the function in your code?

I call it in another script. The script:

local FBan = require(game:GetService("ServerScriptService"):WaitForChild("FBanModule"))

FBan.AddAnonymeBan("achdef")

There’s your issue (I believe?), you send a string instead of Player Instance which is what your function expects.

Do I just remove .Name? Or no?

Yes, remove .Name. You could also just add your name to the table by default for testing:

FBan.AnonymeBanned = {
    ['achdef'] = true,
}

It didn’t print because some type of error occurred before the print. Make sure to keep an eye on the output to debug errors.

The console is more good. I did only see the error on the console.