All MSI desktops with preload Windows can be activated by default. If the Window is not activated, please check following suggestions:

Check the network status. Please connect to internet to activate Windows key.

Please make sure the [System Date and Time] are correct. The time setting could be adjusted in BIOS menu as below.

Power on the device and press [Delete] to enter [BIOS Setting] → Select [SETTINGS] → [System Status] → Reset system date and time → Save and restart the computer → Try to activate the Windows key again.

Check whether the user upgraded hardware by himself, for example memory, SSD, wireless network card etc. If yes, please remove updated hardware and install original hardware to test again. Then, check whether the error disappears.

If you are unable to activate Windows 10, the Windows Activation troubleshooter might help. Please select [Start] → [Settings] → [Update & Security] → [Activation]. Then, please choose [Troubleshoot]. Please also refer to the article: Using the Activation troubleshooter

Restore system to factory setting then try to activate the key again. Please refer to the article: How to recovery the operating system?