diff --git a/application/loginform.class.inc.php b/application/loginform.class.inc.php
index 1ba4c4590..51f1e3832 100644
--- a/application/loginform.class.inc.php
+++ b/application/loginform.class.inc.php
@@ -31,7 +31,7 @@ class LoginForm extends AbstractLoginFSMExtension implements iLoginUIExtension
 	 */
 	protected function OnReadCredentials(&$iErrorCode)
 	{
-		if (Session::Get('login_mode') == 'form') {
+		if (!Session::IsSet('login_mode') || Session::Get('login_mode') == 'form') {
 			$sAuthUser = utils::ReadPostedParam('auth_user', '', 'raw_data');
 			$sAuthPwd = utils::ReadPostedParam('auth_pwd', null, 'raw_data');
 			if ($this->bForceFormOnError || empty($sAuthUser) || empty($sAuthPwd))
@@ -51,9 +51,10 @@ class LoginForm extends AbstractLoginFSMExtension implements iLoginUIExtension
 				$this->bForceFormOnError = false;
 				exit;
 			}
-
+			Session::Start();
 			Session::Set('login_temp_auth_user', $sAuthUser);
 			Session::Set('login_mode', 'form');
+			Session::WriteClose();
 		}
 		return LoginWebPage::LOGIN_FSM_CONTINUE;
 	}
diff --git a/sources/application/Helper/Session.php b/sources/application/Helper/Session.php
index dec7f4c31..970803475 100644
--- a/sources/application/Helper/Session.php
+++ b/sources/application/Helper/Session.php
@@ -55,7 +55,8 @@ class Session
 	 */
 	public static function Set($key, $value)
 	{
-		$sSessionVar = &$_SESSION;
+		$aSession = $_SESSION;
+		$sSessionVar = &$aSession;
 		if (is_array($key)) {
 			foreach ($key as $sKey) {
 				$sSessionVar = &$sSessionVar[$sKey];
@@ -63,12 +64,13 @@ class Session
 		} else {
 			$sSessionVar = &$sSessionVar[$key];
 		}
+		$sSessionVar = $value;
 		if (!self::$bSessionStarted) {
 			self::Start();
-			$sSessionVar = $value;
+			$_SESSION = $aSession;
 			self::WriteClose();
 		} else {
-			$sSessionVar = $value;
+			$_SESSION = $aSession;
 		}
 	}
 
@@ -111,7 +113,8 @@ class Session
 	 */
 	public static function Get($key, $default = null)
 	{
-		$sSessionVar = &$_SESSION;
+		$aSession = $_SESSION;
+		$sSessionVar = &$aSession;
 		if (is_array($key)) {
 			foreach ($key as $SKey) {
 				$sSessionVar = &$sSessionVar[$SKey];
@@ -134,7 +137,8 @@ class Session
 	 */
 	public static function IsSet($key): bool
 	{
-		$sSessionVar = &$_SESSION;
+		$aSession = $_SESSION;
+		$sSessionVar = &$aSession;
 		if (is_array($key)) {
 			foreach ($key as $SKey) {
 				$sSessionVar = &$sSessionVar[$SKey];