The error appears when required thin capitalisation details have not been completed in the International Dealings Schedule (IDS).
Follow the below to resolve:
Open the tax return and navigate to Schedules.
Click on IDS.440783 – International Dealings Schedule.
Click Next until you reach Section D: Thin Capitalisation, questions 35c & 35 cont’d.
Tick Yes or No for all questions in this section.
Save and revalidate the return.