The tape can become stuck by partly engaged tapeheads etc., if the mechanism stops mid-cycle.
This typically happens when belts are getting worn, and wheels are slipping.
Drawer out, from below, through the tiny holes, see if you can rotate the
left flywheel/capstan by pushing it with a small screwdriver or similar tool.
It should be rotated clockwise (seen from above). One rotation is usually enough to release the mech.
It may be necessary to hold the flywheel using something else – a cottom bud or so – while
shifting to the next push of the screwdriver, because the belt will have an “elastic” effect on the flywheel.
Martin