diff --git a/lang/dutch.php b/lang/dutch.php
index 7e1bb6d..de4dec0 100755
--- a/lang/dutch.php
+++ b/lang/dutch.php
@@ -140,6 +140,8 @@ define("Index_01","aangemeld als :");
 define("Login_01","Uw certificaat kon niet gecontroleerd worden.");
 define("Login_02","Uw certificaat is ingetrokken.");
 define("Login_03_No_Org_Certs","Organisatie (OA) certificaten worden niet aanvaard door CATS omdat deze niet eenvoudig naar een gebruikersaccount te herleiden zijn.");
+define("Login_04_No_Server_Certs","Your certificate does not contain an Email field, you are probably using a server certificate.<br />".
+                                  "Server certificates cannot be used to log in to CATS since they do not identify a person.");
 define("Menue_01","Help");
 define("Menue_02","Aanmelden");
 define("Menue_03","Afmelden");
diff --git a/lang/english.php b/lang/english.php
index d78effe..859acbb 100755
--- a/lang/english.php
+++ b/lang/english.php
@@ -144,6 +144,8 @@ define("Index_01","logged in as :");
 define("Login_01","Your certificate could not be validated.");
 define("Login_02","Your certificate has been revoked.");
 define("Login_03_No_Org_Certs","Organisation certificates are not accepted for CATS since they cannot be easily traced to a user account.");
+define("Login_04_No_Server_Certs","Your certificate does not contain an Email field, you are probably using a server certificate.<br />".
+                                  "Server certificates cannot be used to log in to CATS since they do not identify a person.");
 define("Menue_01","Help");
 define("Menue_02","Login");
 define("Menue_03","Logout");
diff --git a/lang/french.php b/lang/french.php
index d2ecf1b..40ede5a 100644
--- a/lang/french.php
+++ b/lang/french.php
@@ -144,6 +144,8 @@ define("Index_01","Connect
 define("Login_01","Votre certificat n'a pas pu être validé.");
 define("Login_02","Votre certificat a été révoqué.");
 define("Login_03_No_Org_Certs","Les certificats d'organisation ne sont pas acceptés pour le CATS car ils ne sont pas directement liés à un compte utilisateur.");
+define("Login_04_No_Server_Certs","Your certificate does not contain an Email field, you are probably using a server certificate.<br />".
+
 define("Menue_01","Aide");
 define("Menue_02","connexion");
 define("Menue_03","déconnexion");
diff --git a/lang/german.php b/lang/german.php
index 91a23c0..c1444b6 100755
--- a/lang/german.php
+++ b/lang/german.php
@@ -143,6 +143,8 @@ define("Index_01","eingeloggt als :");
 define("Login_01","Ihr Zertifikat konnte nicht überprüft werden");
 define("Login_02","Ihr Zertifikat wurde wiederrufen");
 define("Login_03_No_Org_Certs","Organisations-Zertifikate werden von CATS nicht akzeptiert, da sie sich nicht einfach einem Benutzerkonto zuordnen lassen.");
+define("Login_04_No_Server_Certs","Ihr Zertifikat enthält kein Email-Feld, vermutlich handelt es sich um ein Server-Zertifikat.<br />".
+                                  "Server-Zertifikate werden von CATS nicht akzeptiert, da sie keine Person identifizieren.");
 define("Menue_01","Hilfe");
 define("Menue_02","Login");
 define("Menue_03","Logout");
diff --git a/lang/spanish.php b/lang/spanish.php
index 1133fe0..d4a8d07 100755
--- a/lang/spanish.php
+++ b/lang/spanish.php
@@ -139,6 +139,8 @@ define("Index_01","registrado como :");
 define("Login_01","Su certificado no pudo ser validado.");
 define("Login_02","Su certificado ha sido revocado.");
 define("Login_03_No_Org_Certs","No se aceptan certificados de organizaciones para los CATS ya que no pueden ser relacionados fácilmente con una cuenta de usuario.");
+define("Login_04_No_Server_Certs","Your certificate does not contain an Email field, you are probably using a server certificate.<br />".
+                                  "Server certificates cannot be used to log in to CATS since they do not identify a person.");
 define("Menue_01","Ayuda");
 define("Menue_02","Iniciar sesión");
 define("Menue_03","Salir");
diff --git a/login.php b/login.php
index c0a6a30..0fd2bdd 100755
--- a/login.php
+++ b/login.php
@@ -13,6 +13,8 @@ include ("functions/acceptLogin.php");
 
         if (isset($_SERVER["SSL_CLIENT_S_DN_O"])) {
           echo '<h5 class="centered"><br />'.Login_03_No_Org_Certs.'</h5>';
+        } elseif(!isset($_SERVER["SSL_CLIENT_S_DN_Email"]) {
+          echo '<h5 class="centered"><br />'.Login_04_No_Server_Certs.'</h5>';
         } elseif( $user_id ){
         $sql="SELECT * FROM user where `user_id`='".$user_id."' and `root`='".$root."' ";
         $query = mysql_query($sql);