We're using Sage for one of our monthly VAT returns. When we did the first MTD return (April 2019) the GOV.UK screens appeared asking for authorisation and codes sent to our mobile phone. The screen said that once in place the authroisation will last for 18 months. We've just done the May 2019 MTD return and had to go through all the authorisation screens again. I wasn't expecting to have to do this for 18 months. Has anyone else submitted their second MTD return? Did you have to go through the authorsation again? What software are you using?