I have created a connection for SharePoint Online: Site Collection Administration in the Connection Manager. I used an account that is a global admin, and receive no errors upon saving the connection. I added a couple of user owners. Then I put that action in my workflow. All runs results in an Unauthorized request for connection..., the status changes to Suspended with details of ServiceNoResponse. Has anyone gotten this action to work?
Did you try running the workflow with the account that has "Global Admin" permissions? It seems you are trying to create a site collection, only either SharePoint service admin or Global admin create the site collection.
Yes, I have attempted to run the workflow as a global admin user and also by a Sharepoint Online Admin user account. Both result in the same failure , "Unauthorized request for connection".
Then issue could be with the connection or workflow, better check the documentation again and re-create it.