Hello,

If the expense account is not set up, this error will appear. Examine the parameters you added to the account for expenses in settings. Alternately, make sure you have added an expense account to the product category or its parent category that you are utilising. 

For further information regarding expense in Odoo, please refer the below documenthttps://www.cybrosys.com/odoo/odoo-books/v17/expenses/#:~:text=The%20Odoo%2017%20Expenses%20module,with%20payments%20for%20future%20transactions.

Hope it helps.

Hi,

As per the error message, it is raised when account_id is not set when creating the invoice line. So please make sure that the accounts are set for the product's/product categories.

Enable Full accounting:https://www.youtube.com/watch?v=sLetAnqo9m8

Thanks & Regards