In ArcGIS Pro, attempts to add a feature layer to a map from Portal for ArcGIS fail with the following error message returned:
Error: Failed to add data: <Service URL>
Ensure the ArcGIS Server service is running before adding the feature layer to the map
Repair the broken feature layer's data source in ArcGIS Pro
Ensure the layer's source is not broken, which is indicated in the Contents pane with a red exclamation point icon next to the layer. Repair the broken data sources for the layer if it cannot be added to the map. Refer to ArcGIS Pro: Repair broken data sources for layers and tables for more information.