diff --git a/includes/openid-connect-generic-client.php b/includes/openid-connect-generic-client.php
index e05786f..79ae264 100644
--- a/includes/openid-connect-generic-client.php
+++ b/includes/openid-connect-generic-client.php
@@ -45,7 +45,7 @@ class OpenID_Connect_Generic_Client {
 	 */
 	function make_authentication_url() {
 		$separator = '?';
-		if ( stripos( $this->endpoint_login, '?' !== FALSE ) ) {
+		if ( stripos( $this->endpoint_login, '?' ) !== FALSE ) {
 			$separator = '&';
 		}
 		$url = sprintf( '%1$s%2$sresponse_type=code&scope=%3$s&client_id=%4$s&state=%5$s&redirect_uri=%6$s',