Unable to add feature layer to api key

[FactSetResearchSystems]

Hi, I have hosted a feature layer and created an api key. Now I am trying to add the feature layer to the api key by following below steps:
- Click on Edit the api key.

- Click on "set content icon scopes" 

- Add the hosted feature layer

- Click on Add button

After clicking on add button, I get an error notification. Below is the screenshot:

[LaurenBoyd]

Hi @FactSetResearchSystems -

A couple of things to verify:

1. Are you logged into the site with your developer account (not ArcGIS Online organizational account)? You can only do this with a developer account noted here: https://developers.arcgis.com/documentation/mapping-apis-and-services/security/api-keys/#arcgis-cont...
2. Does your developer account own both the API key and the hosted feature layer? You can only access private content that you own with API keys: https://developers.arcgis.com/documentation/mapping-apis-and-services/security/api-keys/#arcgis-cont...
3. Is the layer editable? You can only access content with API keys and your developer account if they are read-only (not editable): https://developers.arcgis.com/documentation/mapping-apis-and-services/security/api-keys/#available-c...