2016 brake controller

I have read no less than 100 posts about these controllers. But i think my error is unique. Here is my situation. 2016 Platinum. I was towing a Gulfstream 21mdb about 4k pounds loaded. W as 50 miles from the end of a trouble free 1800 mile tow and I got the attached error. So I had no brakes no matter what i did to the controller. Not sure what to do next. Go to trailer guy or Toyota dealer? Any ideas?

 

Did you check the braking system on the trailer?

 

Or the connector from your trailer to truck. Bumps "can" make them move unfavorably...just spit-balling ideas...

 

I had that exact issue after a blowout that damaged wiring. After chasing a phantom short in the harness I gave up and ran new wire entirely between the axles. It solved the problem and I’ve been good for a few years now.