Merge pull request #276158 from boris-bazilevskiy/doc-update-may24

clarify domain validation part & fix FQDNs in example

Author: prmerger-automator[bot]

articles/communication-services/how-tos/telephony/domain-validation.md

@@ -6,7 +6,7 @@ author: boris-bazilevskiy
 
 ms.service: azure-communication-services
 ms.subservice: pstn
-ms.date: 10/02/2023
+ms.date: 05/23/2024
 ms.topic: how-to
 ms.custom: include file
 ms.author: nikuklic
@@ -23,8 +23,7 @@ To use direct routing in Azure Communication Services, you need to validate that
 When you're verifying the ownership of the SBC FQDN, keep in mind that the `*.onmicrosoft.com` and `*.azure.com` domain names aren't supported. For example, if you have two domain names, `contoso.com` and `contoso.onmicrosoft.com`, use `sbc.contoso.com` as the SBC name.
 
 Validating domain part makes sense if you plan to add multiple SBCs from the same domain name space. For example if you're using `sbc-eu.contoso.com`, `sbc-us.contoso.com`, and `sbc-af.contoso.com` you can validate `contoso.com` domain once and add SBCs from that domain later without extra validation.
-Validating entire FQDN is helpful if you're a service provider and don't want to validate your base domain ownership with every customer. For example if you're running SBCs `customer1.Azure Communication Services.adatum.biz`, `customer2.Azure Communication Services.adatum.biz`, and `customer3.Azure Communication Services.adatum.biz`, you don't need to validate `acs.adatum.biz` for every Communication resource, instead you validate the entire FQDN each time. This option provides more granular security approach.
-
+Validating entire FQDN is helpful if you're a service provider and don't want to validate your base domain ownership with every customer. In that case, you must validate base domain only in resource you control. For example if you're running SBCs `customer1.acs.adatum.biz`, `customer2.acs.adatum.biz`, and `customer3.acs.adatum.biz`, you don't need to validate `acs.adatum.biz` for every Communication resource, instead you validate `acs.adatum.biz` in your resource (resource you own), and your customers validate the entire FQDN as a domain name in their resources. This option provides more granular security approach.
 
 ## Add a new domain name