I have seen two, J1772 plugs where the locking latch was broken off. This often jams the locking lever that leaves the 'presence' signal OFF. The presence signal prevents hot disconnects that can arc the power pins. Once jammed down, the EVSE won't work:

By pressing ahead of the pivot pin, the lever rocks up and presence switch goes ON. This allows the EVSE to work.
Bob Wilson

By pressing ahead of the pivot pin, the lever rocks up and presence switch goes ON. This allows the EVSE to work.
Bob Wilson