Howdy, Usually there would be a cooldown of at least a month as one would suspect if you recently changed the email. However if you haven't changed it recently then you should be able to, if you aren't able to and haven't recently changed it then something's probably gone wrong. if it's telling you it was changed recently then you'll just need to wait the usual thirty days and try again. if it still doesn't work, you'd be best opening a support ticket with Mojang directly to have it changed.
