diff --git a/src/keycloak/openid_connection.py b/src/keycloak/openid_connection.py
index d7e27ee..583afcd 100644
--- a/src/keycloak/openid_connection.py
+++ b/src/keycloak/openid_connection.py
@@ -300,6 +300,7 @@ class KeycloakOpenIDConnection(ConnectionManager):
                 verify=self.verify,
                 client_secret_key=self.client_secret_key,
                 timeout=self.timeout,
+                custom_headers=self.custom_headers,
             )
 
         return self._keycloak_openid