Email settings show whether your sender domain is verified and ready to send. Complete sender verification before using an address as the default.
Before connecting a custom email domain, add and verify the exact domain in Settings > Domains. Email settings list active, verified store domains that are not already connected to this store for email.
Register and verify the domain
Choose your verified store domain and follow the email-domain setup. A verified website domain still needs email-sender verification. The email domain remains pending until the required DNS checks succeed.
A root domain and each subdomain are separate email domains. For example, example.com and test.example.com must each be added and verified before they can be connected.
Copy the DNS records shown in Email settings into your domain provider exactly as displayed. Keep the required records in place after verification. DNS changes can take time to propagate.
After the records have propagated, select Verify domain. Once verification succeeds, you can create more sender addresses on that domain.