Hello there, steve362.
To ensure successful VAT return submission through QuickBooks, you can check HMRC email, set up MTD, use correct sign-in credentials, verify VAT number with HMRC, review recent VAT returns, check for specific errors and outstanding obligations, and review the status page regularly.
You can visit this article for a step-by-step guide: Take action and fix MTD issues and errors in QuickBooks Online.
Additionally, you can check this article to guide you through making adjustments to your current VAT settings in the program: Make VAT adjustments in QuickBooks Online.
Let me know if you have further questions about VAT in QuickBooks Online, feel free to circle back. I'm always here to help.
