I have a bit of clients hosted offshore and seems a mix between high latency and IPS default chunk size was causing larger uploads to his -200 error. The fix I found for this issue was to patch plupload options to 5mb instead of the default. This will also add in a retry so if one chunk fails it will retry that chunk instead of failing. This is likely only needed when very specific environment conditions are met, but I needed it so maybe it will help you as well.

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