Hi Peter, Most of the layers come from ArcGIS Online Hosted Feature Services (Provinces and Territoires of Canada, World Countries (Generalized), Australia State Boundaries 2018, etc). Layers based on these services are some of the layers that can't be added. Others layers are based on a feature service from our organizational ArcGIS Server and others are based on a hosted feature service I created by uploading a shapefile to ArcGIS Online. So all 60-something layers are based off these 7-8 different feature services. I do not see any network level errors in Developer tools. Technical Support with Esri is managed by our IT team, so I'll check with them about logging a case. Thanks again for your help, it is much appreciated. Phil
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