https://vatoto.com/forums/user/454007-sir-sap/
https://vatoto.com/forums/user/507243-sirmitch/
both validated
likely something is not right with your device/mouse and you send multiple registration/validation requests with each click, so with your emails already being in use and your validation requests already processed, you only get to see errors from further attempts at using them.
also, you log in with the username and password, not your email - and if your username and password still won't work, try using password recovery once and logging in with the temporary password you get from it (you can later change back to the one you want in your profile settings)