Game Center account
On the "Internet Accounts" Section of System Preferences, it says that I have two game center accounts with the same Apple ID.
MacBook Pro 13″, macOS 10.15
The blank game center account on top was associated with a previous email account I used as the primary email account for my Apple ID. I went to the Keychain Access app on my MacBook Pro and double-clicked on com.apple.account.GameCenter.token. Then I renamed the email address information in com.apple.account.GameCenter.token with the previous email address. I went to "Internet Accounts" on System Preferences and clicked the - button while the blank game center account associated with a previous email address was selected. I pressed ok when my MacBook asked me if I wanted to delete the game center account. Then the problem was fixed.
