What causes "Error posting assignment grades" in instructure/canvas-lms?

Retry the mutation once; the failure is often transient during job processing.

instructure/canvas-lms · error · GraphQL::ExecutionError

Error posting assignment grades

Error message

Error posting assignment grades

What it means

Catch-all failure branch of postAssignmentGrades: when the code path reaches the final else, the Gradebook posting service did not return a success result, so a generic 'Error posting assignment grades' ExecutionError is raised instead of a granular message.

Solutions

Retry the mutation once; the failure is often transient during job processing.
Check server logs (Canvas error reports) for the underlying exception raised by the posting service.
Verify submissions exist and grades are in a postable state; contact admin/inspect progress jobs if it persists.

Example fix

// before
await postAssignmentGrades({input});
// after
try {
  await postAssignmentGrades({input});
} catch (e) {
  if (e.message === "Error posting assignment grades") {
    // retry once, then surface logs to the user
  }
}

Defensive patterns

Strategy: retry

Try / catch

try { await post(); } catch (e) { if (e.message === 'Error posting assignment grades') { await retryWithBackoff(post, 2); } else throw e; }

Prevention

Retry transient failures with backoff before alerting users.
Correlate with server logs / error reports for root cause.
Verify posting prerequisites (grades published, submissions present) before calling.

When it happens

Trigger: The internal postgrades service returns a non-success result (e.g. internal submission posting failure) after passing earlier validations.

Common situations: Transient backend/data issues while enqueueing posting; unexpected return shape from the posting service during upgrades.

Related errors

AI-assisted analysis of instructure/canvas-lms@1c9f0bb801 (2026-09-15). Data as JSON: /api/errors/2b5a2a27ae8818df. Report an issue: GitHub.

Appendix: source

Thrown at app/graphql/mutations/post_assignment_grades.rb:84

    posting_params = {
      graded_only: !!input[:graded_only],
      section_names: sections&.pluck(:name)
    }

    if progress.save
      progress.process_job(
        assignment,
        :post_submissions,
        { preserve_method_args: true, priority: Delayed::HIGH_PRIORITY },
        progress:,
        submission_ids:,
        posting_params:,
        skip_content_participation_refresh: false
      )
      { assignment:, progress:, sections: }
    else
      raise GraphQL::ExecutionError, "Error posting assignment grades"
    end
  end
end

View on GitHub (pinned to 1c9f0bb801)