Hi Atakan Coşguner,
Thank you for posting in the Microsoft Community Forum.
You can try using a recovery account:
Windows Server domain controllers typically have a recovery account setting, which can be used to reset the domain administrator password.
Log in to the domain controller and navigate to Active Directory Users and Computers (ADUC).
Locate the domain administrator account, right-click, and select "Properties."
Switch to the "Account" tab and find the "Recovery" account option.
Enter the credentials for the recovery account, then use it to log in and reset the domain administrator password.
Best regards
Neuvi Jiang