Email alias already exists - error

Email alias already exists - error

Hi, I've been getting the captioned error when trying to add a 'hello' alias for my email. I'm migrating my emails over to Zoho and that Alias is the only one I'm having an issue with. Not sure why I'm getting that error, and I've already deleted that address from my previous server just as part of my troubleshooting. Any help would be beneficial!