Hey all, Ash from Fathom 
Just jumping in to say @philh is absolutely right — our Discourse setup docs were a bit out of date (you no longer need to add our script src to your CSP). Thanks for letting us know @philh!
We’ve now updated the guide to remove that step and hopefully avoid any future confusion. We’ve also added a step-by-step walkthrough for getting Fathom set up on Discourse, based in part on the helpful info shared in this thread — so thanks for that, too!
You can find the updated guide here:
https://usefathom.com/docs/integrations/discourse
If anyone stumbles across this thread and needs a hand getting set up, feel free to reach out to our support team — we’re always happy to help 