fix(management): EWS write gate requires username:password credentials

src/ZB.MOM.WW.ScadaBridge.ManagementService/ManagementActor.cs

@@ -2213,7 +2213,7 @@ public class ManagementActor : ReceiveActor
         {
             throw new ManagementCommandException(
                 "EWS transport requires Host to be an absolute https:// EWS endpoint URL "
-                + "(e.g. https://mail.example.com/ews/exchange.asmx).");
+                + $"(e.g. https://mail.example.com/ews/exchange.asmx); got '{config.Host}'.");
         }
 
         // The EWS sender authenticates with HTTP Basic only — no OAuth2 flow exists
@@ -2223,6 +2223,19 @@ public class ManagementActor : ReceiveActor
             throw new ManagementCommandException(
                 "EWS transport supports only Basic authentication; set AuthMode to 'basic'.");
         }
+
+        // Same split semantics as the delivery adapter: FIRST colon only, because a
+        // domain-qualified user name contains none but a password legitimately may.
+        // Without this the common mistake — flipping an existing SMTP row (whose
+        // Credentials is a bare password) to Ews — would persist happily and then park
+        // every single notification at delivery time.
+        var credentialParts = config.Credentials?.Split(':', 2) ?? [];
+        if (credentialParts.Length != 2 || credentialParts[0].Length == 0 || credentialParts[1].Length == 0)
+        {
+            throw new ManagementCommandException(
+                "EWS transport requires Credentials in 'username:password' form "
+                + "(username may be 'domain\\user').");
+        }
     }
 
     /// <summary>