Distinguishing a slow upload from a failed one

Note whether the progress indicator changes, whether the server acknowledges completion, and how long each stage takes. A stalled upload, repeated error, and slow processing after transfer are different symptoms.

Test with one permitted small file and record its type and approximate size. Avoid repeatedly submitting a large file if it might still be processing, and never post private file contents. Compare another network only when safe and practical.

At what stage does progress stop?