Cannot open the door from inside or outside - mechanical faulty

Issue : If the customer cannot open the door from inside or outside with mortise lock, and it looks like mechanical issue

1. We need to check the door thickness.
   1. 1. If it’s too thin, then the handle shaft might be jammed by the outbody and inbody handle.
      2. If it’s too thick, then the handle shaft might not be engaged with the handles.
2. If the door thickness is alright, but it worked before, but suddenly not working,
   1. 1. Check the spring pin. If there is no spring pin, the handle shaft might be moved to the outbody and inbody handle might not be engaged.
3. If all good, but still not working,
   1. 1. Please check the mortise location. If it’s not at the centre of the door, then one side might be too far from the handle. And it won’t be engaged.