Can you share a screen of that blocked page / error page?
If you navigate to the CF dasboard → WAF → Overview, you should see the blocked firewall event.
Could you share which Rule ID or Ruleset is shown in the details when you click to “expand” that particular firewall event in the table view from the bottom of the page?
You’d need to troubleshoot and create an exception in whatever security setting at CF dashboard you modified which is blocking the access.
Just to clearify, is the CSP to question here or Cloudflare WAF (Managed Rules)?