Yes, you absolutely can add a business back after deleting it from the Forwardly system.
To reconnect a business to Forwardly, simply follow the steps you took to add it in the first place. Keep in mind that any previous manual entries will have been removed when you disconnected the accounting software from Forwardly.
Warning: Once disconnected, all manually edited entries will be deleted from Forwardly. This deletion is permanent and cannot be undone even if the business is reconnected.