Hello NickH. The message indicates that the digital link between QuickBooks and HMRC has expired and needs to be updated so you can send your data. You can resolve this by reauthorizing the connection to get your filing back on track.
From your QuickBooks, go to Taxes and then choose Set up MTD. After that, choose "Authorise now" and select Continue. Once the new window opens, sign in with your MTD Government Gateway user ID and password. Then, click Continue and press Give permission. When you see that you are connected, select Continue and then Go to Taxes.
If you have further questions, let us know in the comments.
