firebase cloud functions http error code 403

Try firebase logout and firebase login. This fixes the issue sometimes if you're trying to run it on a different account.

You need to login to Firebase CLI through the account that initiated the billing for the project (wherein you are trying to deploy the functions).

Even though you may have multiple accounts (in Firebase console), the signing through firebase CLI has to be done through main billing account. I tried this and it solved the error! Hope this helps!