I try adding people as Sandbox Testers to my App, but Apple keeps saying that they already exist on the team, even though they're not. It always show "A user with this email address already exists on the team" It keeps happening with every address I try.

I recently created an app for iOS, and i tasted it a few times before on my phone but since I bought my Apple Developer Account i get those errors. I already re-activated my account in the Xcode settings. How can I fix this?