After setting up Auth0 custom domain, the DNS record reflection time was about 5 minutes.

Tenant Settings - Custom Domains

When you set up a custom domain from https://manage.auth0.com/dashboard/jp/YOUR_NAME/tenant/custom_domains, the following message is displayed.

Before you can use a custom domain with Auth0, you must verify that you own your domain. This helps to prevent unauthorized use. To verify your ownership, add one of the verification records listed below to your domain's DNS record.

Error Message

Error!Your verification record was not found. You might need to wait a few minutes before we can discover it.

After setting up CNAME on Amazon Route53, I was able to verify on Auth0 in about 5 minutes.

Domain Verification

Domain Verification

The domain auth.example.com was successfully verified. Please take into account that the configuration process might take 1-2 minutes to complete

That’s all from the Gemba.