On your “vat settings” page (not the “HMRC” page) is the “use MTD” box ticked and your connected tax account selected in the drop down box? (The “linking to your vat profile” bit at the bottom of this article)
On your “vat settings” page (not the “HMRC” page) is the “use MTD” box ticked and your connected tax account selected in the drop down box? (The “linking to your vat profile” bit at the bottom of this article)