We experienced the same thing last month on our drive down to Florida.
We have Bigfoot levelers.
I called a contact phone number I had of a guy at Bigfoot and he said one of the levelers was probably down 1/16th of an inch causing the alarm to sound.
He instructed me to tighten the bolt on the bottom of each leveler pad.
I had gotten off the highway and really didn't want to go crawling under the rig in freezing temps so I thought I would simply lower each leveler a short distance and then retract them and see if that would solve the issue.
Luckily that is all it took. Never heard the alarm the rest of the trip.
2018 Newmar Canyon Star 3513