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There is probably a defective paper presence sensor. It fails to register the presence of paper that should be sensed as passing into a certain location (near the rear of the feed tray, it seems, or wherever the paper stops.) So the printer deduces that the paper has become crumpled up, stuck, or misfed somewhere before that point, and stops working with a 'paper jam' error.
This will probably require service-repairing for the printer.
You could try a rest-reset: turn the printer Off. Leave it Off for a while (preferably several hours or overnight.) Then turn it On and see if the error is cured. (This is not likely to work, and don't bother trying it twice or more.)