Help! My client keeps saying that my Summoner Name does not exist.

I am looking to make a smurf and today i went and made it. I successfully created the account, but i ran into issues while trying to create my Summoner Name. I followed all the requirements

3+ letters No profanity No usage of "Riot" And used only letters, numbers, and spaces

I do not want to share the name because I really love it and would like to be the one to have it. But it was 4 letters, no profanity, or usage of "Riot". When I click submit, it said "This name IS in use" so I went onto this account and looked up the name and it said it DID NOT exist...I went into my smurf account and tried again, same thing happened. So i went back to my main account and went to add a friend put the name in and sure enough, it doesn't exist. I don't know whats wrong. The name does have "é" in it, is it because of the accent? Because I've seen other summoner names with accents in then work just fine...Please help