999999: Error executing function. Failed to execute (FeaturesToJSON)

Error Message

In some instances, when using the Features To JSON tool on certain feature class data with the Output to GeoJSON option checked in ArcGIS Pro, the following error message is returned:

Error:   
ERROR 999999: Error executing function. 
Failed to execute (FeaturesToJSON).

Cause

The error occurs due to the parametric (true) curve in the feature geometries. The GeoJSON format does not support parametric curves.

Solution or Workaround

As a workaround, convert the curves in the feature class to straight line segments. There are two options to do this: using the Feature Class To Shapefile tool, or the Densify tool. Use the output from either tool as input for the Features To JSON tool to convert the features to the GeoJSON format.

Using the Feature Class To Shapefile tool
The Feature Class To Shapefile tool copies the features from the input feature class to a new shapefile. This tool converts the curves in the input feature class to straight line segments in the output shapefile, as shapefiles do not support true curves.

Using the Densify tool
The Densify tool densifies curves in the feature class by replacing them with line segments. This tool modifies the input feature class. The following image shows a densified feature. The curve feature geometry is converted to straight line segments.