The IP’s listed on the hook creation page (https://manage.auth0.com/#/hooks) appear to be either incorrect or not fully complete.
I whitelisted all the IP’s on that page but my hook could not connect to the database until I added the IP’s listed for my region from this page. Auth0 IP Addresses for Allow Lists
This is confusing because the documentation in the link above says:
Please be sure to allow inbound connections from the region-specific set of IP addresses listed in the Dashboard. The specific set of IP addresses you should use is provided when you create your new Custom Database Connection, Hook or Rule.