LTI integration with Open edX returns Error 500

[sowibrahima]

I installed BigBlueButton 3.0 using https://github.com/bigbluebutton/bbb-install v3.0 with the LTI framework.
After going to https://bbb.mydomain.com/lti/rooms/xml_config, the secure_launch_url is set to:

<blti:secure_launch_url>https://bbb.mydomain.com/lti/rooms/messages/blti</blti:secure_launch_url>

I enabled the BigBlueButton integration with Open edx by supplying consumer key and consumer secret defined using -t MY_KEY:MY_SECRET, then for launch url, I used https://bbb.mydomain.com/lti/rooms/messages/blti.

When I open the LTI page via Open edx, I get a blank page with:

https://bbb.mydomain.com/apps/rooms/1?launch_nonce=170087769450400684191759502760 500 (Internal Server Error)

Here are the series of requests executed from the browser: