Integration with Autotask Invoice app is returning this: Can't get Account xxx. {"errors":["IntegrationCode is invalid."]}. is this QB or Autotask?

I appreciate you reaching out to us, Ghayes. I'll be glad to point you to the appropriate team to ensure you can integrate Autotask with QuickBooks Online (QBO).

Since Autotask is the connector, I recommend reaching out to their customer service team to assist you in resolving the error message when linking their app to QBO. 

Moreover, you can also run reports to get a complete picture of your business's various transactions, including sales.

Please don't hesitate to drop by the Community whenever you have further concerns about app integrations. We're always here to answer your queries. Stay safe, and have a wonderful day ahead.

I'm encountering the same thing.  Issue started on Wed evening 11/29 Pacific time. Please provide follow-up if you find a solution.   I've tried voiding/resubmitting on the AT side with no luck. I've tried clearing the queue, and manual syncs on the QBO side, with no luck.  

I'm checking with AT support, but I suspect that this is a QBO issue.

Autotask PSA support has been FANTASTIC!!!   instructions sent to me to reactivate the API user in autotask and then disconnect in quickbooks and reconnect.   Autotask is well aware of the issue.  QB support says to contact autotask.