Hello Nasr!
There are four possible causes for your issue.
Possible cause 1
The bandwidth is insufficient and the buffering icon is displayed frequently.
Solution
Switch the play mode to smooth on the PC.
Possible cause 2
The PC hardware performance is insufficient and the CPU usage is high.
Solution
Switch the play mode to smooth or use a PC with better CPU performance.
Possible cause 3
The video format is 1080p60 BP. Chrome does not support 1080p60 BP videos whose bit rate is 4 Mbit/s or above.
Solution
Use Firefox or Internet Explorer.
Possible cause 4
The frame rate of the video is 1080p
@30 fps or 1080p@60 fps, but the PC fails to play the video because its display performance is insufficient.
Solution
Switch the play mode to smooth or use a PC with a discrete graphics card.
Hope this possible solutions can solve your issue!