@Stephen TCC 

The returned error being displayed is from the QBO API.

Try doing GSearches on the topic:

https://www.google.com/search?q=qbo+api+An+account+you+chose+for+a+billable+expense+doesn%27t+have+an+income+account+associated+with+it.

https://quickbooks.intuit.com/learn-support/en-us/other-questions/trying-to-create-expense-from-a-receipt-i-am-getting-an-error/00/950277

https://help.developer.intuit.com/s/question/0D54R00007MnISFSA3/cannot-create-an-estimate-via-api-a-business-validation-error-has-occurred-while-processing-your-requestdetailbusiness-validation-error-an-account-you-chose-for-a-billable-expense-doesnt-have-an-income-account-associated-with-it

Thanks again @Troy Tessalone 

The problem with the above suggestion is that “customer” is not a billable expense.

Products and services have income accounts associated with them.

Customers do not.

The Zap requires the customer info file from QBO to populate the duplicated estimate. For some reason the Zap is seeing the customer as a product or service.

@Stephen TCC 

The Zap step returning the errors is trying to “Create Estimate” for Customer ID 614 in the screenshot.

Possible guidance from ChatGPT:

Thanks for your reply @Troy Tessalone,

I am stumped on what that action is to be. A “customer” is not a billable expense and it is not possible to associate an income account with a customer contact file in QBO. 

Hi @Stephen TCC 

Based on the error message, you need to take action in QBO for the Customer with the ID you are testing with.