diff --git a/Stack/Opc.Ua.Core/Security/Certificates/CertificateValidator.cs b/Stack/Opc.Ua.Core/Security/Certificates/CertificateValidator.cs
index 565a60fee..2fd0ae67a 100644
--- a/Stack/Opc.Ua.Core/Security/Certificates/CertificateValidator.cs
+++ b/Stack/Opc.Ua.Core/Security/Certificates/CertificateValidator.cs
@@ -1923,7 +1923,7 @@ private static ServiceResult ValidateServerCertificateApplicationUri(X509Certifi
                 {
                     return ServiceResult.Create(
                         StatusCodes.BadCertificateUriInvalid,
-                        "The Server Certificate ({1}) does not contain an applicationUri.",
+                        "The Server Certificate ({0}) does not contain an applicationUri.",
                         serverCertificate.Subject);
                 }