Unable to edit a value in a field in ArcGIS Online Map Viewer

Description

When editing a field in ArcGIS Online Map Viewer, the Update button is disabled.

Cause

The field contains a domain with a list of values. This restricts the field with a limited number of possible values.

Solution or Workaround

Delete the list of values

Delete the list of values from the field to remove the limit of possible values. Refer to ArcGIS Online: Delete a list of values for further instructions.

Add the new custom value to the list of values

Add the desired value by editing the list of values. In the List of Values: <field> window, click + Add, and type a new value for Label (displayed value) and Code (stored value). Refer to ArcGIS Online: Edit a list of values for further instructions.