UPDATE - 4pm 17 March: we have now been informed that this issue has been resolved, and that all MTD for VAT services are available as normal.
HMRC have provided us with the following update regarding problems with the MTD for VAT service:
We previously advised you that we would be undertaking scheduled maintenance to HMRC’s digital services in order to deliver a number of iterative enhancements to the functionality of the Making Tax Digital (MTD) for VAT service.
Unfortunately, following successful delivery of this functionality over the weekend, an issue has been identified that is impacting the ability of some MTD for VAT customers to submit a return.
We are working to resolve this issue as soon as possible. In order to enable a fix to be delivered, we have been required to shutter the ‘Return Submission’ element of MTD for VAT. As a result, it is currently not possible for customers or agents to submit a VAT return through the MTD service.
All other elements of the VAT service (such as sign-up and payment) remain open. There is no interruption to applications for the VAT deferral New Payment Scheme. The MTD for ITSA service is unaffected.
We expect the full service to return on the morning of Thursday 18th March. If this situation changes, we will notify you immediately.