QuickBooks credentials are not configured on the server yet.
Connection flow
Start QuickBooks authorization
This page now starts the live OAuth flow. It creates a short-lived state cookie on the server, redirects the customer to Intuit's authorization screen, and returns them to the registered callback URI after consent.
Use the QuickBooks accounting scope for the private app.
Register https://simplytables.vertec.io/oauth/callback as the OAuth redirect URI in the Intuit app settings.
Generate and validate OAuth state server-side before starting the flow.
Persist the QuickBooks realm connection after the callback exchange.