I paid for same day ACH but it didn’t post. Why not? If your ACH transfer didn’t post the same day, there are several possible explanations: It was not received from the transferring institution before the 1:45pm CT deadline There was an incorrect or changed account number on the order Insufficient funds (NSF) were available in the account from which you were transferring We were unable to locate an active account The account you attempted to transfer the funds into had been closed.