I think these are instructions for connecting to Portal, which Is different than ArcGIS Online.

You are right sir. Can I use the same process for a Esri ArcGIS Online instead of the portal? Im still getting a greyed out screen.

It looks like you use the Esri ArcGIS Portal (Template) web service instead of the Esri ArcGIS Online template. Your URL is

https://YOUR_PORTAL_HOST/portal/sharing/rest/oauth2/authorize?response_type=code

while it should be

https://www.arcgis.com/sharing/rest/oauth2/authorize?response_type=code&expiration=-1

Steps to follow are:

• Go to AGOL, create an app and retrieve the client id and secret.
  • Click New item, Application, Other application.
  • Enter title, tags and summary.
  • Go to tab Settings.
  • Scroll down to page and click Registered Info.
  • Collect the values from app ID and app Secret.
• Start FME,  create a new web service based on "Esri ArcGIS Online" using the App ID and app Secret acquired in the previous step.
  • Click Tools, FME Options..., tab Web Connections, Manage Services...
  • Click on "+", Create From..., Esri ArcGIS Online.
  • Enter a Web Service Name, enter the App ID in the Client Id field and the app secret in the Client Secret field.
  • Apply.
  • Click on Test... to check if the Web Service is functioning.
  • Close if test turned out ok.
• Add Web Connection.
  • In the Web Connections window, click "+" to add a new web connection.
  • Choose the web service created in the previous step.
  • Enter a Connection Name.
  • Click Authenticate... and log in.

I followed your instructions but Im still getting a grey screen when testing and/or authenticating. Could it be a permissions or security issue?

What happens when you test with the Esri ArcGIS Online web service (instead of the one you created yourself using your own app id / secret)?

What version FME do you use?

When testing using the esri webservice Im also getting a grey screen. Using 2021.0. I tried it using 2019.1 and there the connection to ArcGIS webservice works.. weird.

Hi @John Smith​ 

Can you verify if the grey screen is happening with only Web Connections?

Can you open FME Help web page (from Help --> FME Workbench)?

One option is to try the in build an ArcGIS Online web connection and select "Verify SSL Certificate" as shown below

What do you mean with "Can you verify if the grey screen is happening with only Web Connections?"

When I open the FME Help web page Im also getting a grey screen.. the option Verify SSL Certificate I dont have. The Parameter option is greyed out.

@John Smith​ Thanks for sharing that information, so it appears that for some reason the application is being blocked to load any content. We will need to investigate this further within your environment using some debugging tools(Fiddler/Wireshark). I would like to escalate this to a support ticket.