Welcome to the Auth0 Community!
Thank you for checking all of the immediate possible issues for not receiving the verification email. Are you using the built in Auth0 email provider, or an external SMTP? The Auth0 email provider is used for testing purposes and we do recommend setting up a custom email provider, as they tend to be more reliable and can solve these issues, as mentioned in the following Community posts as well:
Let me know if you are still encountering the issue afterwards, or if there are any failures within the tenant logs ( Monitoring → Logs )
Hope this helped!
Gerald