'The submission of this document has failed due to departmental specific business logic in the Body

Hello IT Department, 

 Welcome to the Community page, 

It is sounding like your trying to file the VAT through the VAT 100 report, which is wrong. You need to go to VAT> FILE VAT and choose the MTD option. As long as you have a version 2019 and above you should be fine and have no more issues.