Stuck "Enter your Apple ID password" I just changed the password of my Apple ID. 

When I started using my Mac, several minutes later, the system preferences asked me to enter my password to continue using iCloud. after entering my new password, it hanged. Restarting the mac did not even work, I had to hard shut down the machine.

After the machine is rebooted, it asks me once again to enter the password of Apple ID...

Could anyone help?

Edit1:
So it is always stuck as follows:
From the screen image, I would try a couple of things since you should be able to log in to the Mac and do things other than iCloud. Press cancel in the dialog and then check the date/time on the Mac. It should be within 2 minutes of reality if possible.

Then go to Safari and check at https://icloud.com to be sure you can log in and the account isn't locked or having issues.

At that point, you might need to clean out your keychain or try again in the iCloud preference pane. Worst case, you might need to get on the phone/web chat with iCloud support if it's a problem with your account or Apple's servers.