Messaging: The notification permission was not granted and blocked instead

This indicates that you have blocked the push notifications permission on the deployed website. It's messaging.getToken() that is likely erroring out (see the docs for more).

If you're using Chrome, you should be able to click the lock to the left of the URL and go to "Site Settings" where you'll see a bell icon with the notification settings for the site:

This may be set to "Block" and you would need to change it to "Allow" instead.

Make sure you're not in an incognito tab - in that case the permissions dialog (Allow/Block) won't show up (in Chrome at least)