Second to Tom Rupp's comments about levelling - the prior owner of our 2307 made a point of walking me through the procedure she used to level the trailer, and said she had door issues if she didn't follow it. We've used her procedure for the last 3 years and never had a problem with either the upper or lower door bindng.
1. level the trailer side to side with spacers under the wheels on the low side (we later discovered Anderson leveling wedges and love 'em - https://andersenhitches.com/products/camper-leveler
2. level the trailer front to rear using the tongue jack
3. crank the corner supports down until they touch the ground, then just enough farther that they're pushing against the ground a bit.
4. raise the upper section.
We've had the same issue with the door opening that Angel mentioned - finally figured out that the curb side of the upper section wasn't adequately supported when it was lowered and was flexing on rough pavement. Resolved the issue by adding a 3rd outrigger support just ahead of the front wheel / behind the entry door on the curb side