I had a piece of filament break off in the tube and could not unload it so I removed the extruder and pulled out the piece. Reloaded filament and started to recalibrate. The head went to left and tried to keep going. It made a horrible thumping and would not stop until I turned the unit off. I then tried to home it, same result. Tried to reset to factory settings then home it and same result. Any ideas?
This can happen when the end stop of the X-axis (i.e. the minimum end stop on the left) has moved/bent/broken/un-connected.
Please look into this answer of question Flashforge Adventurer 3 - how to replace X-axis endstop. The X end stop is a module inside the print head, please look if the connector is dislodged or something.