Description
The Input Features were unable to be projected to the coordinate system for the Candidate Features because the projections are incompatible. The analysis has been finished in the WGS_1984_Web_Mercator_Auxiliary_Sphere coordinate system.
Solution
If you want to use a coordinate system other than WGS_1984_Web_Mercator_Auxiliary_Sphere, consider reprojecting both datasets into an alternative coordinate system to which both inputs can successfully reproject.