This article is written for the following specific error:
If your listing rules are selected to "Set Guest as Customer" AND if a Customer that Bnbtally created in QuickBooks Online is inactive (archived) or merged with another customer, this will cause a Sync Object Error in Bnbtally. When this happens, Bnbtally is unable to re-create the Sync Object until the Customer for the Sync Object is reset.
How to Resolve this Issue
Go to Sync Manager and search for the Sync Object with the error. Select to "view" the Sync Object.
Within the Sync Object, select the button "Run Diagnostic"
Under the "Guest as Customer" test, you will find there is an error "Unable to find the specified Guest as Customer". Next to the error message, select the button "Reset Customer". This will create a new Customer for this Sync Object in your QuickBooks Online Company and will automatically rollback the Sync Object.
After this Sync Object is rolled back, you can then select to sync (or re-create) the Sync Object.