Win10 Technology Preview cannot be activated how to fix

The Win10 technology preview has been released, and it has been popular among many users. Although it is still in the testing stage, there are still many users who can't wait to upgrade the system to Win10. However, since the Win10 system is not yet a formal version, there are still many problems.
The Win10 Technology Preview currently only provides a public key that can be successfully activated using this key. In general, the network is activated by default when you install it. If you encounter "Unable to activate Windows." Please try again later, you can try to reactivate Win10 using the public key.
1. Press win+X or right click on the Start menu button and select “Command Prompt (Administrator)”.

2. Enter the following code: slmgr /ipk NKJFK-GPHP7-G8C3J-P6JXR-HQRJR and press Enter to enter.

After these two steps, Win10 can be activated, and you can start using this latest version of Windows. However, in the process of using Win10, you may encounter various problems, so you should actively find a solution.