I have this issue also with ArcGIS Pro 2.2. engl. version. I created a new project with basemaps, server-connections, wms-connestions, several layouts, an own style-file and had some FC references in the basemap. Afther all this configurations I tried to share a project template (Erstellen einer Projektvorlage—ArcGIS Pro | ArcGIS Desktop) once in the cloud, once local but everytime the error "External sharing process failed" occured. With a blank projekt was the sharing process succesful. So I deleted one at the time all what I configurated and located the problem. The problem ist the style-file (Speichern einer Style-Datei—ArcGIS Pro | ArcGIS Desktop). My new *.stylx file (even when its empty) blocked the sharing process. After I deleted all the new created style-files in the project, the sharing process worked fine for the cloud and local. I also tried to share the style-file for the web (Freigeben eines Web-Styles—ArcGIS Pro | ArcGIS Desktop) and I get an error and it failed!
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