Comment 3 for bug 1697909

Not to hijack this thread, but we encountered the error message above in a Mahara/Canvas implementation, along with a similar-but-different parameter issue. Mentioning it here in case others encounter also.

After adding the Canvas-specific parameters to the module_lti_launch.php file, we found Admin could connect, but a regular user received an error as above except citing the missing parameter, "lis_course_offering_sourcedid".

This parameter was missing from the module_lti_launch.php file as well.

We note that lis_course_offering_sourcedid is described in Section 6 of the Basic LTI Implementation Guide, Version 1, May 17, 2010 - Final (see: https://www.imsglobal.org/specs/ltiv1p0/implementation-guide).

Have added that parameter to the file as well as:

'lis_course_offering_sourcedid' => new external_value(PARAM_TEXT, 'LTI lis_course_offering_sourcedid', VALUE_OPTIONAL),

which seems to have cured the problem.

Looking forward to the "long term solution" alluded to above!