Enable map for offline use

[rk2800]

I've been creating simple projects using ArcGIS Pro desktop but have been unable to create an offline map for use on Field Maps. My current workflow is as follows: Select basemap>add a kml file> share to web. 

When I open Field Maps Designer in the esri enterprise environment, offline capabilities are not enabled. I have been receiving the following errors: "Layer type is not supported" and "The basemap does not contain credentials."

How can I avoid these errors and access both the basemap with KML offline in Field Maps?

[rk2800]

Update: Errors were resolved after converting KML to shapefile then to feature class. I was able to get both the basemap and feature class to project in the same datum and prevent errors or warnings when sharing to web. 

Now the issue is enabling offline capabilities within Field Maps Designer. The errors received are: 

Layers: Sync is not enabled

Basemap: The basemap does not contain credentials.  

Any idea how to fix this and enable offline capabilities?