Hi kn.anwar,
if you are sure that the product key is correct, you can try activating OS using the telephone activation method.
To do this, please follow these steps:
- Open the Command Prompt as an administrator.
- Type "slui 4" (without quotes) and press Enter.
- Select your country or region from the list and click Next.
- Call the telephone number provided and follow the instructions to activate OS.
For more information about phone activation, please see Support Center Contact Info. | Microsoft Learn.
Hope it helps.
Kind regards,
Lei