Passenger side sliding door stop working and hard to open manually

have you checked the fuses for the door and is there a switch to disengage the motor from the door?

...clearly there is some debris slowing things down...what you must do is inspect it with a small screwdriver and shopvac...release any parts of chocolate bars....wedding rings...over ripe pears that need to be removed....with the shop vac~

lubricate with Tri-flow spray lubricant w/teflon...don't overdo it~

as our pal Bradley suggests, make sure the motor ain't burnt~ the fuse would be kaput...and the motor would test with a load there, but would not turn and smell burned~

Turned switch off and checked fuse, it was good.

can you see if the motor still runs with a "power probe"?