Moodle versions: 4.x
LTI Provider: 1.3/advantage
Background: In 2021 I posted an issue with LTI 1.1/1.2 Empty service url (https://moodle.org/mod/forum/discuss.php?d=430048) .
Cause: We found out that this is due to a reset option on the LTI consumer side. This particular LMS implemented that the LIS_result_sourced_ids will be send without a the serviceurl because they don't expect a result back.
Moodle vs Moodle
As posted in https://moodle.org/mod/forum/discuss.php?d=430048 I could not replicate this issue from Moodle - Moodle.
The problem we see: is that when the LMS consumer is wrongly configured this is the reason why a grade is not being received.
What we suggest: that when the serviceurl is empty, when the student goes into the course a notification will appear. That due to configuration, there will be no result send back. and they should contact their organisation.
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Are you having this issue as well? please vote on my tracker (https://tracker.moodle.org/browse/MDL-77476) . Do you think there is a better solutions, please let me know!