1. Open Developer tools

2. Developer tools box will open at the bottom of the window.

3. Select Network tab in developer tool bar.

4. Check if Network record log is enabled. Incase it is black (which means it is disabled), click on it to enable.

4. Network record log button would be red once it is enabled

5. Now, open video page which is having issue while playing.

6. Once you see the error , right click anywhere inside the developer tools box and select save as HAR with content.