Problem: ArcGIS Online web map hangs indefinitely after clicking the Settings tab on the Item Details page
When attempting to access the Settings tab located in the Items Details page for an ArcGIS Online web map, the Settings tab hangs indefinitely.
This issue occurs when a hosted feature service is removed from ArcGIS Online, but the layer that corresponds to the hosted feature service is not removed from the web map.
Additionally, if the web map is not saved after the hosted feature service is deleted from ArcGIS Online, an error message, "<layer name> could not be added to the map" appears when opening the web map in the map viewer.
Solution or Workaround
To resolve this issue, open the web map in the map viewer, and save the web map. Saving the web map updates the list of layers, making the Settings tab accessible.