An unknown has error occurred when I try to unlock my AppleID

Get support and assistance from Apple directly, see  -> Contact Apple for help with Apple ID account security

Contact Apple for help with Apple ID account security - Apple Support

Your Apple ID is locked. The only way to fix a locked Apple ID is to change the password. The easiest way to change the password is through a trusted device. Please see this: Change your Apple ID password - Apple Support

From the image... it appears whatever you entered for your birthdate is not matching what you originally set it up with. When you setup your account originally did you use a different birthdate?