AO_100301: Merge Layers requires the same geometry type for all inputs
The two selected layers do not have the same geometry type.
There are three possible geometry types for a layer: points, lines, and polygons. The two selected layers must have the same geometry type.
Solution
To resolve the error, do one of the following:
Select input layers that have the same geometry as each other.
Use Find Centroids to create point features from lines or polygons.
Use Create Buffer to create polygons from points or lines.