Do you know if it is hydraulic or electric? If electric, the cables might be loose. In any event, as a temporary cure, I would cut a couple of pieces of 2x4 and place them above the slide when closed.
Just be sure to remove B4 you try to open.
Life is a journey, not a destination.
2005 Georgetown 359ts
Bill & Virginia, Kentucky
Nights camped in 2011...78 , 2012...73,
Nights camped in 2013...123, 2014 ...101