I have been making digital Vat returns to HMRC via Quickbooks for years, why is Quickbooks now asking me to register for digital Vat returns again?

Hello Sales249, 

Welcome to the Community page, 

It is more than likely that it will be the 18 month reauth you will need to do. If you have a look at this article two articles they will help resolve the issue. Set up MTD for VAT in Quickbooks Online and connect to HMRC and also this one Take action status when connecting to HMRC for MTD.