Problem with slide

we bought a 2015 Bighorn 5th wheel in March of 2016.
Things were good until this summer, we had a problem getting the slide in ( see photo's )
It' only the one slide on right side of unit.
Can anyone tell me; a) what caused this b) how to repair.

Hi SMPMS,

Welcome to the Heartland Owners Forum.

Your pictures didn't come through. Forum software blocks pictures until you have 2 or 3 posts approved by a moderator. In the meantime you can post them to Google photos or Photobucket or some other service and link to them in a post here.