Fix Entra ID link: whatis-entra-id -> whatis

Author: msmbaldwin

articles/security/fundamentals/azure-domains.md

@@ -27,7 +27,7 @@ For firewall configurations, use the wildcard patterns shown in the **Subdomain*
 |Service  |Subdomain  |
 |---------|---------|
 |[Azure Access Control Service](https://azure.microsoft.com/blog/one-month-retirement-notice-access-control-service/) (retired)|*.accesscontrol.windows.net|
-|[Microsoft Entra ID](/entra/fundamentals/whatis-entra-id)|*.graph.windows.net / *.onmicrosoft.com|
+|[Microsoft Entra ID](/entra/fundamentals/whatis)|*.graph.windows.net / *.onmicrosoft.com|
 |[Azure API Management](https://azure.microsoft.com/services/api-management/)|*.azure-api.net|
 |[Azure BizTalk Services](https://azure.microsoft.com/pricing/details/biztalk-services/) (retired)|*.biztalk.windows.net|
 |[Azure Blob storage](../../storage/blobs/storage-blobs-introduction.md)|*.blob.core.windows.net|