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Usually a key indicator of where/what is causing the jam is to look for any indications of where the jam focus is.

If there's a single point, the folds of the jam tend to point to it so it's well worth trying to "read" the folds and paper crumpling to help nail down the problem area and then examine it carefully.

You may also have the paper rising up slightly due to some object in the paper path and this can lift the paper above the slot it would normally exit through and cause the same sort of pile up. So it's worth looking in the area that the paper passes over too.