Merge pull request #187738 from duongau/patch-1

AFD add custom domain - add missing "_"

Author: PRMerger17

articles/frontdoor/standard-premium/how-to-add-custom-domain.md

@@ -56,7 +56,7 @@ A custom domain is managed by Domains section in the portal. A custom domain can
 
     :::image type="content" source="../media/how-to-add-custom-domain/validation-state-pending.png" alt-text="Screenshot of domain validation state pending.":::
 
-1. Select the **Pending** validation state. A new page will appear with DNS TXT record information needed to validate the custom domain. The TXT record is in the form of `_dnsauth.<your_subdomain>`. If you're using Azure DNS-based zone, select the **Add** button and a new TXT record with the displayed record value will be created in the Azure DNS zone. If you're using another DNS provider, manually create a new TXT record of name `dnsauth.<your_subdomain>` with the record value as shown on the page.
+1. Select the **Pending** validation state. A new page will appear with DNS TXT record information needed to validate the custom domain. The TXT record is in the form of `_dnsauth.<your_subdomain>`. If you're using Azure DNS-based zone, select the **Add** button and a new TXT record with the displayed record value will be created in the Azure DNS zone. If you're using another DNS provider, manually create a new TXT record of name `_dnsauth.<your_subdomain>` with the record value as shown on the page.
 
     :::image type="content" source="../media/how-to-add-custom-domain/validate-custom-domain.png" alt-text="Screenshot of validate custom domain page.":::