Can't figure out how to ignore a user

My question:

I'm trying to figure out why I can't add the user "Caveman" to my ignore list—every single time I try, I just get hit with this error: The user 'Caveman' was not found in the database. Please go back and correct this problem. You may want to check out the member list.

Maleficent replied:
You should probably head over to the Help! subforum, since technical glitches like that are strictly handled by the administrators.

So... do I actually ask?

velvetgull9 said:Unfortunately for you, the system won't let you add a username to the Ignore list if it contains any diacritics or non-standard characters.

In other words—to put it bluntly—your entire headache stems from that little accent mark. 😉

Fine 😉

velvetgull9 said:Too bad, but you can't put a username on the Ignore list if it uses special characters or anything non-standard.

Basically, your issue is just that letter "ć". 😉

Why not just ban them altogether???

I mean those special characters and weird symbols??

What the hell do you mean by "non-standard characters"???

"c" is totally standard (it’s literally in the manual)

edit: here, let axmi explain how this works😬
edit2: axmi aaaaaxmiii 🎉 🎉