The angle of the chamfer face to adjacent faces is too large or too small.
The chamfer edge angle is the angle between the chamfer face and the support face. (This is the angle you specify while modeling a chamfer in SOLIDWORKS.) When the chamfer edge angle is too large or too small, the chamfer face appears to be part of the support face. The error message appears when the angle is too flat (less than 6°) or too steep (greater than 89.999°).
Example
Minimum edge angle:
Example
Maximum edge angle:
