Udemy video course material will not play. (Windows)

[lem3]

Udemy courses that worked correctly in whatever version of SeaMonkey I was using 8 (or so) months ago now fail to play. Each lesson of a course begins with a 5-7 second video prelude specific to that course. This runs correctly, but when the actual course content begins the screen goes black, the Status line is "waiting for page-events-ustats.udemy.com".
Debug actions include:

1. Clear cache
2. Disable AV
3. Start SeaMonkey with default profile
4. Start SeaMonkey in Safe mode
5. Change useragent to Firefox with User Agent Switcher
6. Change useragent to Firefox through general.useragent.override.udemy.com in about:config
7. Toggled media.autoplay.enabled (I had set it to False)
8. Disabled uBlock

When the screen blanks the following appears in the Error Console:

Code: Select all

Timestamp: 2/18/2019 6:36:49 PM
Error: XML Parsing Error: no root element found
Location: https://www.udemy.com/api-2.0/users/me/subscribed-courses/22461/lectures/108790/progress-logs
Line Number 1, Column 1:
Source File: https://www.udemy.com/api-2.0/users/me/subscribed-courses/22461/lectures/108790/progress-logs
Line: 1

OK, there's an error in the code (maybe?). The videos used to play in SeaMonkey and still do in current Firefox and Chrome: I don't expect to get much sympathy from Udemy support. Anything else I should try or just use FF or Chrome?

[ElTxolo]

....The videos used to play in SeaMonkey and still do in current Firefox and Chrome: I don't expect to get much sympathy from Udemy support. Anything else I should try or just use FF or Chrome?

• A known problem with no apparent solution:
• Udemy video course material will not play. (GNU/Linux)
  
  
  
  
  
  
  
  
  Cheers!!

[therube]

No indication (in the other thread) that anyone tried 2.53.
Might try that (in a new, clean Profile).

Could even be something as mundane as a useragent.
Might try spoofing that to a plain FF UA.

[lem3]

Could even be something as mundane as a useragent.
Might try spoofing that to a plain FF UA.

That was Steps 5 and 6...