Usually, after allowing Admin Tools to access your ArcGIS Online Organization, you should immediately have access to the tools. However, if you are taken to the main page of Admin Tools, and are still forced to use the Sign In Button, which results in an endlessly spinning loading animation. Please check your "Allow Origins" settings, outlined below.
Sign In to your ArcGIS Online Organization and Select the Organization tab.
Select "Edit Settings."
Select the "Security" Tab.
Find the "Allow Origins" Section
Ensure that this field is BLANK, and "No Domains Configured" is shown. (Alternatively, you can attempt to add https://apps.geopowered.com to this domain list)
If you've performed these steps, and still have problems signing in to Admin Tools, please email us at firstname.lastname@example.org, or call us at 1-844-GEOJOBE.