Spiderman No Way No Home

All I want to do is initiate a remote session WITHOUT having any software pre-installed on the remote machine. I have TeamViewer installed on my machine, I've created a 'QuickSupport' module and have a custom URL. I texted the URL to the remote user, they entered it into their web browser and they said now there's just a spinning progress wheel. They clicked the "Retry" link, but nothing happens, just the spinning wheel...