SGA XBlock: "Download All Submissions" triggers 500 Internal Server Error

[abdullah8590]

When a learner submits a file through an SGA (Staff Graded Assignment) XBlock and a staff/instructor user attempts to download all submissions via the staff grading view on the live site, the action fails with a 500 Internal Server Error. The error occurs on the prepare_download_submissions API handler call.

STEPS TO REPRODUCE

1. Log in to Studio on sandbox.openedx.edly.io with an admin/staff account.
2. Open (or create) a course in Studio and add an SGA (Staff Graded Assignment) XBlock to a unit.
3. Publish the unit so it is visible on the LMS.
4. Log in as a learner account and navigate to the course unit containing the SGA XBlock.
5. Upload and submit any file through the SGA XBlock submission form.
6. Log back in as a staff/instructor account and navigate to the same course unit on the live LMS.
7. In the SGA staff grading view, click the "Download All Submissions" button.
8. Observe the error.

EXPECTED RESULT
Clicking "Download All Submissions" should trigger a file download (i.e., a ZIP archive) containing all learner-submitted files.

ACTUAL RESULT
The browser receives a 500 Internal Server Error response. The failing request is the call to the prepare_download_submissions handler endpoint on the SGA XBlock.

ENVIRONMENT
sandbox.openedx.edly.io

XBLOCK
edx-sga

AFFECTED ROLE
Staff / Instructor

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FAILING REQUEST — CONFIRMED FROM NETWORK TAB

HTTP 500 Internal Server Error

Method	POST
URL	https://sandbox.openedx.edly.io/courses/course-v1:openedx+NTC-7+2026/xblock/block-v1:openedx+NTC-7+2026+type@edx_sga+block@dda6888aea6045449c12c73c10b360d3/handler/prepare_download_submissions
Handler	prepare_download_submissions
Block usage key	block-v1:openedx+NTC-7+2026+type@edx_sga+block@dda6888aea6045449c12c73c10b360d3
Response status	500 Internal Server Error

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