Error Prompt: CMN.ATO.IITR.300031 - Total business or personal services income, and description of main business activity are required.
Where industry code is present, there must be a description of main business activity, amounts at primary production or non-primary production income in the Business income and expenses section; or Net Personal Services Income

Suggested Solution:
1. Go to Business > Business Income & Expenses section. If Label P2 - "Description of main business or professional activity" has been filled (example per image below is "Agricultural services nec - Code 05290).

2. You need to fill also "Business Name of main business" (P5) and "Business address of main business" (P6) to resolve the error.