I have secured services in ArcGIS for Server that I would like to add to our organisation's ArcGIS Online.
When adding those secured services, ArcGIS Online does not provide the option to store credentials with service items.
All the references mention that I am supposed to be able to store the credentials if my secured services are externally accessible.
We have web adaptor configured for our ArcGIS for server. How can we tell if our services are externally accessible?