Welcome to the JOF.
Some trailers are very low. If the trailer is low at the rear, the first thing is to check if the front of the trailer is high. The trailer should be level or slightly nose down. If the trailer is level, maybe lowering the front a bit would make the difference.
Other things to consider: Is the trailer heavily loaded? Can some of the load be moved closer to the front of the trailer? Is the trailer suspension sagged due to age or damage causing the trailer to be lower than designed? Is there room for larger diameter rims and tires?
That's all I got. Hope something in there helps.
Sherm & Terry w/rescues Steve (std Poodle) & Eydie (min Schnauzer)
2015 Jay Flight 27RLS (Camped: 102 nights 2015, 90 nights 2016)
2006 Ford F350 6.0 PSD, Lariat, 4WD, CC, LB, SRW, auto., Camper pkg.