If yes, please check your Cloudflare WAF events, so you can see what is triggering the firewall and edit a rule (If it is a custom rule) or allowlist yourself if is a Managed one. You customize the Managed ones too, if you have at least the Pro plan.
If there’s no Cloudflare page and logs at your Cloudflare firewall, then the 403 Error is coming from your origin and you need to view its logs from here to troubleshot it. If you don’t manage your origin, ask your developer or hosting provider for help.