Windows 10: System always asking to activate windows 10

Hello.
I buy an Windows 10 Pro 64bit dvd and i did a clean install in my desktop. I insert the key-code, it was activated, all perfect. That was like a month ago.
A few days ago, i notice that water-mark in the right-lower corner of the screen telling me to activate Windows 10.
At the first time i insert the key-code again and it was activated, all well.
One or two days later, once again the water-mark activation warning. This time i activated directly. All well...
Now every day that f****** water-mark appear in the middel of the session, allways asking to activate Windows.
Does it makes any sence to you guys? Has anyone face a similar issue? Any advice? Drinks anyone...?
Thanks.

:)

 

Window Activation

• Why my system always keep on asking to activate window.
• why microsoft didn't trust to their users often asking for activation.

 

Problem with Windows update -2018-01 Cumulative Update for Windows 10 Version 1709 for x64-based Systems (KB4056892)

Problem with Windows update- 2018-01 Cumulative Update for Windows 10 Version 1709 for x64-based Systems (KB4056892). Can't be installed, it is always asking for restart...

[Moved from: Windows / Windows 10 / Install, upgrade, & activate]

 

Where did you buy this Windows 10 x64 Pro DVD with key?

And, please, the exact wording of the watermark as it appears. Every word, please.

 

I buy that copy in the same computer store where i also buy all the desktop components. And believe me, it is a LEGAL copy.
As for the watermark, is the tipicall message:

Activate Windows
Go to PC settings to activate Windows
[Go to PC settings]

 

If you are still having problems see Activation troubleshooting - Windows 10 Forums