A Canvas issue has caused previously working Kami LTI integration to fail to load student documents for teachers. We've notified Canvas of the issue and we've rolled out a temporary fix of the issue.
This would show "An Error occurred while validating the launch of Kami" error.
The earliest report of the issue was on Wednesday, 2nd December, 9am Eastern time. With the vast majority of the cases reported on Thursday, 3rd December Eastern time. This has been fixed.