You are receiving the below error message when attempting to publish an invoice.
Tax code is not correct, it should be a number but the code specified is 'T0'
Non-VAT registered companies that are integrated with an accounting software.
This is typically caused by an incorrect VAT code being allocated for non-VAT registered companies.
If you are seeing this error on your invoices please follow these steps to clear it, and successfully publish:
Click the Integrate button on your company homepage. If you do not have access to this button, you will need to ask the billing user of the account to either amend your permissions, or carry out these steps themselves.
On that page, ensure the correct VAT codes have been entered into these dropdown boxes.
Click the green 'Save' button at the bottom.
Republish the affected invoices.
If you do not see the options above, please ensure that the company has 'Not Registered for VAT' selected in your Company Settings. Further guidance on this can be found here.