Enter a valid EA ID

Hello everyone,

I tried to change my username from EpicJo1 to JoToX. However, I get an error message asking me to enter a valid ID.

Since I already use the name JoToX on all other platforms (see attachment), I don't understand why the change isn't possible here. I also don't get a notification that the name is already taken—which makes the whole thing even more confusing.

I'm asking for help in resolving this issue.

Thank you very much and best regards,
JoToX