To publish your Instapage landing page to your Yahoo! domain, you will need to create a CNAME record in the DNS settings.
1. Sign in and go to your Services page;
2. Click the Domain link;
3. Locate the A and CNAME Records section then click the Add link;
4. Now you need to enter any subdomain name you want in the Source field and “secure.pageserve.co” in the Destination field, then click Add.
Success! Now you can publish your Instapage landing page on your custom domain.