diff --git a/templates/LoginForm.php b/templates/LoginForm.php
index 6594623cb3ccfcefd7eb9cc6085f824dfc7b40fb..08e11ad55c73e439b90128e45cb335afce418fca 100644
--- a/templates/LoginForm.php
+++ b/templates/LoginForm.php
@@ -87,7 +87,7 @@ if (null !== $this->data['errorCode']) {
                                     <?php
                                     } ?>
                                     <input type="hidden" id="username" name="username"
-                                           value="<?php echo htmlspecialchars($this->data['username'], ENT_QUOTES); ?>"/>
+                                           value="<?php echo htmlspecialchars($this->data['username'] ?? '', ENT_QUOTES); ?>"/>
                                     <?php
                                 } else {
                                     ?>