Multi site error when registering users
I was getting this message on a multi site install that I was working on: Usernames can only contain lowercase letters (a-z) and numbers. I haven’t dug into this yet, it seems like this popped up in WP 4.4. Here is how I have gotten around it: function amr_wpmu_validate_user_signup( $userinfo ) { if ( array_key_exists( […]