Hey @EdenCapital,
Based on the 403, I assume that you are trying to access a canister that is not available under ic0.app. Just replace ic0.app with icp0.io and try again (see this thread for some explanation).
If the issue persists, then I need more information from you on what you are actually trying to do (e.g., what URL you are calling). For example, in your snippet above, getting a 307 that redirects to dashboard.internetcomputer.org is the expected behavior.