Why is my Twitter or Facebook account already in use?
You may have a created a second Medium account without realizing.
To check this: sign out of Medium > and try to sign in using the social media account in question.
If you did sign up accidentally and you want to delete the duplicate account, go to your settings page > delete the account.
This will free up that Twitter or Facebook account in our database, and you can then create a new account with it.