Merge pull request #596 from AzureAD/SJAIN/regional-endpoint-fix

regional endpoint change to always use login.microsoft.com

Author: siddhijain

msal4j-sdk/src/main/java/com/microsoft/aad/msal4j/AadInstanceDiscoveryProvider.java

@@ -22,7 +22,7 @@ class AadInstanceDiscoveryProvider {
     private final static String AUTHORIZE_ENDPOINT_TEMPLATE = "https://{host}/{tenant}/oauth2/v2.0/authorize";
     private final static String INSTANCE_DISCOVERY_ENDPOINT_TEMPLATE = "https://{host}:{port}/common/discovery/instance";
     private final static String INSTANCE_DISCOVERY_REQUEST_PARAMETERS_TEMPLATE = "?api-version=1.1&authorization_endpoint={authorizeEndpoint}";
-    private final static String HOST_TEMPLATE_WITH_REGION = "{region}.{host}";
+    private final static String HOST_TEMPLATE_WITH_REGION = "{region}.login.microsoft.com";
     private final static String SOVEREIGN_HOST_TEMPLATE_WITH_REGION = "{region}.{host}";
     private final static String REGION_NAME = "REGION_NAME";
     private final static int PORT_NOT_SET = -1;
@@ -47,7 +47,9 @@ class AadInstanceDiscoveryProvider {
 
         TRUSTED_HOSTS_SET.addAll(Arrays.asList(
                 "login.windows.net",
-                "login.microsoftonline.com"));
+                "login.microsoftonline.com",
+                "login.microsoft.com",
+                "sts.windows.net"));
 
         TRUSTED_HOSTS_SET.addAll(TRUSTED_SOVEREIGN_HOSTS_SET);
     }
@@ -187,8 +189,7 @@ private static String getRegionalizedHost(String host, String region) {
         //  whereas sovereign cloud endpoints and any non-Microsoft authorities are assumed to follow another template
         if (TRUSTED_HOSTS_SET.contains(host) && !TRUSTED_SOVEREIGN_HOSTS_SET.contains(host)){
             regionalizedHost = HOST_TEMPLATE_WITH_REGION.
-                    replace("{region}", region).
-                    replace("{host}", host);
+                    replace("{region}", region);
 
         } else {
             regionalizedHost = SOVEREIGN_HOST_TEMPLATE_WITH_REGION.