Quick answer: Raise MaxStepHeight on the CharacterMovementComponent to clear the ledge. Also check the step’s collision isn’t a steep face the capsule treats as a wall.
A character walks fine on flat ground but jams against a low curb or the first stair — the movement component refuses to step up.
MaxStepHeight
CharacterMovementComponent → Max Step Height (default ~45 cm). Any obstacle taller than this is treated as a wall, not a step. If your stairs/curbs are taller, raise it — or lower the geometry to fit.
Walkable Floor Angle
The top of the step must register as walkable. If the step’s collision presents a slope steeper than Walkable Floor Angle, the character won’t accept it as ground. Keep step tops flat (or within the angle).
Capsule vs Geometry
The capsule’s radius matters — a wide capsule against a short step can wedge. Visualize collision (show Collision) and check the capsule isn’t catching on a beveled or angled step edge.
Perch Settings
For thin ledges, Perch Radius Threshold and Perch Additional Height control whether the character can stand on an edge. Tune these if the character slides off narrow steps.
Verifying
Walk into curbs and up staircases — the character steps up smoothly. Genuine walls still block. No jamming on geometry within the step height.
“Steps taller than MaxStepHeight are walls. Match the setting to your level geometry — or the geometry to the setting.”
Pick a MaxStepHeight early and have level designers build stairs to it — retrofitting either side later is tedious.