Tried to change my password and didn't work

My EA app recently updated and logged me out, but when I went to change my password it kept saying it contained an unsupported character when it only had the base requirements and no special characters. I managed to change it in the end, but I'm really confused as to why this happened (as an example I put in AreYouReallyOkaymp3 and it said it didn't support it). Has anyone had this/know what was going on?