diff --git a/auth/cas/auth.php b/auth/cas/auth.php
index 6615b755931..9d83dd18294 100644
--- a/auth/cas/auth.php
+++ b/auth/cas/auth.php
@@ -111,6 +111,26 @@ class auth_plugin_cas extends auth_plugin_ldap {
             return;
         }
 
+        // If the multi-authentication setting is used, check for the param before connecting to CAS.
+        if ($this->config->multiauth) {
+            $authCAS = optional_param('authCAS', '', PARAM_RAW);
+            if ($authCAS == 'NOCAS') {
+                return;
+            }
+            // Show authentication form for multi-authentication.
+            // Test pgtIou parameter for proxy mode (https connection in background from CAS server to the php server).
+            if ($authCAS != 'CAS' && !isset($_GET['pgtIou'])) {
+                $PAGE->set_url('/login/index.php');
+                $PAGE->navbar->add($CASform);
+                $PAGE->set_title("$site->fullname: $CASform");
+                $PAGE->set_heading($site->fullname);
+                echo $OUTPUT->header();
+                include($CFG->dirroot.'/auth/cas/cas_form.html');
+                echo $OUTPUT->footer();
+                exit();
+            }
+        }
+
         // Connection to CAS server
         $this->connectCAS();
 
@@ -134,27 +154,6 @@ class auth_plugin_cas extends auth_plugin_ldap {
             return;
         }
 
-        if ($this->config->multiauth) {
-            $authCAS = optional_param('authCAS', '', PARAM_RAW);
-            if ($authCAS == 'NOCAS') {
-                return;
-            }
-
-            // Show authentication form for multi-authentication
-            // test pgtIou parameter for proxy mode (https connection
-            // in background from CAS server to the php server)
-            if ($authCAS != 'CAS' && !isset($_GET['pgtIou'])) {
-                $PAGE->set_url('/login/index.php');
-                $PAGE->navbar->add($CASform);
-                $PAGE->set_title("$site->fullname: $CASform");
-                $PAGE->set_heading($site->fullname);
-                echo $OUTPUT->header();
-                include($CFG->dirroot.'/auth/cas/cas_form.html');
-                echo $OUTPUT->footer();
-                exit();
-            }
-        }
-
         // Force CAS authentication (if needed).
         if (!phpCAS::isAuthenticated()) {
             phpCAS::setLang($this->config->language);