diff --git a/common/rfb/CSecurityTLS.cxx b/common/rfb/CSecurityTLS.cxx
index 9a698f0..9eeb76c 100644
--- a/common/rfb/CSecurityTLS.cxx
+++ b/common/rfb/CSecurityTLS.cxx
@@ -229,6 +229,9 @@
     if (gnutls_certificate_allocate_credentials(&cert_cred) != GNUTLS_E_SUCCESS)
       throw AuthFailureException("gnutls_certificate_allocate_credentials failed");
 
+    if (gnutls_certificate_set_x509_system_trust(cert_cred) != GNUTLS_E_SUCCESS)
+      vlog.error("Could not load system certificate trust store");
+
     if (*cafile && gnutls_certificate_set_x509_trust_file(cert_cred,cafile,GNUTLS_X509_FMT_PEM) < 0)
       throw AuthFailureException("load of CA cert failed");