This Session's transaction has been rolled back due to a previous exception during flush. To begin a new transaction with this Session, first issue Session.rollback(). Original exception was: Can't reconnect until invalid transaction is rolled back. Please rollback() fully before proceeding (Background on this error at: https://sqlalche.me/e/20/8s2b) (Background on this error at: https://sqlalche.me/e/20/7s2a)