No idea, but I did notice something I have not seen before, the circle above the tasks indicator that shows a picture .

Anyway is the game functioning in other respects? 

If not, and you cant fix the problem yourself ,it may help the techies,if you describe it here.

Is the machine working for other programs?

Have you tried doing the usual computer stuff like diagnostics, turning off all other applications, restart the  machine after clearing history and cache etc?

Thu Nguyễn Thị Kim said:

Thanks for reply, WDYWTNTF, but I always cleared history & cache... when my PC ran slowly. I just play game and dont run any other progames at the same time.

Good day! Thank you for the information. You could try to open full-screen mode using the special in-game button or try to change the window scale by a combination "Ctrl" and "+".

Contact us with the result! Thank you in advance!

Thu Nguyễn Thị Kim said:

Thanks Admin. I tried following your instructions, but nothing changed and still was the old error.

Good day!

Thank you for the information.

Send me, please, in PM, the screenshots or video of what are you seeing on your screen after following each of the instructions from my previous message. You can use sites for creating and posting screenshots and paste the screenshot link in the personal message.

Waiting for your message!

Posting images is just like adding pictures to an email, if you can do that, the rest should be easy.

However I do not know if you can send video, though I see no reason why not.

The file should be stored somewhere on the device you use to play the game.

At the top of the page where you time are several icons, the third one with the little inverted triangle is the one you use to add files (or url)  however I have just noticed the next one to it  says  send youtube video.

In case you cant follow my explanation.

There is a post on here, in fact several I think, where Ivar explains how to post images.

Thu Nguyễn Thị Kim said:

I made a video of my screen error, buy this website I cannt send it to You, You can show me how?

Good day!

Answered you in PM.