Onebox error code of 403

The preview function of Onebox for udemy url got an error as below.

“Sorry, we were unable to generate a preview for this web page, because the web server returned an error code of 403.”

Not sure if it’s due to the discourse updating today or the site itself. Here comes the situation.

  1. The udemy site preview works fine before yesterday. Sample url:
    Udemy free coupon code 2021_0502-2 - udemy 限免課程 - StudyCamp 線上學習論壇

  2. The Onebox preview doesn’t work today. Sample url:
    Udemy free coupon code 2021_0503 - udemy 限免課程 - StudyCamp 線上學習論壇

I did some further testing.

  1. youtube Onebox preview works fine

  2. udemy preview on facebook debug tool works fine
    Sharing Debugger - Facebook for Developers

Sample udemy course url for testing: (Weird, the preview works fine here)

Please advice. Thanks a lot!

The update of docker image before and after.
PS: the onebox plugin should be the same

Found a similar issue years ago.

The update info. before & after.
PS: After updating, the onebox failed with 403 error