You are seeing the below error message on your invoice after attempting to publish.
An unexpected error occurred.
Sage Accounting/SBCA integrated companies.
This error is typically caused by something timing out within your company's sync with Sage.
To clear the error, please do the following:
Disconnect your company's integration. You can follow this article here to see how to disconnect your company's integration.
Go ahead and reconnect your company.
Republish the affected invoices.
Please allow a few minutes for the error to clear, and for the invoice to transfer over to Sage.