I got this error on a Route Solve, and I honestly have no idea how to address it. For starters, I wasn't running a Find Best, I was running a Preserve First and Last. I followed "Tranforming Polylines into Route Layers" Esri tutorial, sort of. I was following the steps but using my own data. I have only 2 stops, the train stations at each end of the route, but the route itself is made up of a large number of waypoints. It's my understanding that the only way to put polylines into a Route Analysis layer is to turn the polylines into a series of waypoints, but if I can't even route along waypoints without first ordering them (which, with a dataset of my size, is basically impossible to do manually), then what's the point of having a Route solver?