ArcGIS Collector does not display web maps created in Portal for ArcGIS

Description

When attempting to access a web map from a Portal for ArcGIS organization in ArcGIS Collector, the web map does not display, preventing the viewing of the map.

Cause

This issue occurs if the web map does not meet the conditions required to be displayed in ArcGIS Collector.

To view or edit a web map in Collector, the map owner must add and save at least one editable feature service to the map.

Note: 
When viewing an editable web map in ArcGIS Online, the Edit button displays above the Contents pane, as shown below. 

                                           

Additionally, the feature service must reference the FeatureServer endpoint at REST to allow the web map to be accessible. A feature service has a FeatureServer endpoint if /FeatureServer is appended at the end of the feature service URL, as shown in the following example:

http(s)://ServerName.domain.com/arcgis/rest/services/FeatureServiceName/FeatureServer

For more information, refer to ArcGIS REST API: Appendix - Working with the Feature Server.

Solution or Workaround

To allow the web map to display in ArcGIS Collector, the owner of the feature service must perform the following:

• Enable editing on the feature service. To do so, navigate to the Item Details page in Portal for ArcGIS, and under the Properties section, check the Enable editing and allow editors to option, and click SAVE.

• Ensure the feature service is saved on the web map using the FeatureServer endpoint.

Note:
When making changes to the services on the web map, owners are required to open the web map in Portal for ArcGIS, and save the web map to ensure the changes are saved.