diff --git a/includes/openid-connect-generic-client-wrapper.php b/includes/openid-connect-generic-client-wrapper.php
index 9316e40..e778970 100644
--- a/includes/openid-connect-generic-client-wrapper.php
+++ b/includes/openid-connect-generic-client-wrapper.php
@@ -365,7 +365,7 @@ class OpenID_Connect_Generic_Client_Wrapper {
 		$this->logger->log( "Successful login for: {$user->user_login} ({$user->ID})", 'login-success' );
 
 		// redirect back to the origin page if enabled
-		$redirect_url = esc_url( $_COOKIE[ $this->cookie_redirect_key ] );
+		$redirect_url = isset( $_COOKIE[ $this->cookie_redirect_key ] ) ? esc_url( $_COOKIE[ $this->cookie_redirect_key ] ) : FALSE;
 
 		if( $this->settings->redirect_user_back && !empty( $redirect_url ) ) {
 			do_action( 'openid-connect-generic-redirect-user-back', $redirect_url, $user );