diff --git a/common/source/java/ch/systemsx/cisd/common/ssl/SslCertificateHelper.java b/common/source/java/ch/systemsx/cisd/common/ssl/SslCertificateHelper.java
index 4c701d9ff8dccdf21d1bcd3f36f01a4d006f6208..92bf1fb31945594cd11964af96ce4758cb468995 100644
--- a/common/source/java/ch/systemsx/cisd/common/ssl/SslCertificateHelper.java
+++ b/common/source/java/ch/systemsx/cisd/common/ssl/SslCertificateHelper.java
@@ -92,6 +92,10 @@ public class SslCertificateHelper
         {
             URL url = new URL(serviceURL);
             int port = url.getPort();
+            if (port == -1)
+            {
+                port = 433;
+            }
             String hostname = url.getHost();
             SSLSocketFactory factory = HttpsURLConnection.getDefaultSSLSocketFactory();
             socket = (SSLSocket) factory.createSocket(hostname, port);