Bottom line is you put too much regular house paper down there. Next time use septic safe RV paper or what others have suggested. (it dissolves)
Also, make sure to use the RV toilet packet/chemicals before filling/using the tank next time. Full bowl of water with every paper flush.
You basically have what they call the brown pyramid. The paper built up under the trap and the liquid ran out.
You need to get the paper out. Your most sanitary option is to flush it out as described.
Plan B would be to get some trash picker uppers and pull it up out of the trap through the toilet if there is no liquid.
All else fails. Go to RV supply, buy a thing of tissue dissolver, some RID-X and a magic wand. Make sure the tank is full of liquid and add the chemicals. Let it sit for a few days. Find a campground or a place to dump at. Rinse and repeat.
2011 Coachman Freedom Express 295RLDS- Sold
2015 F-250 FX4 SUPER DUTY 6.2L Gas 4WD SuperCab XL 3.73 rear / 158" WB / 8' bed. Factory anti-sway and brake controller