Cannot Authorise My tax Digital (Going round in circles)

For some time now we have been successfully submitting VAT returns for my small business (Sole Trader) via the My tax digital (formally Portico) and recently were asked to re-authorise via the government Gateway. I have followed the steps about a dozen times and it successfully goes through but then I am asked right at the end to save my VAT number which is correct and then I get this error. Have tried to submit the VAT return still but it just says not Authorised. I cannot now submit my VAT Return and have no idea how to fix this. Any help appreciated. Error below "HMRC response: The client and/or agent is not authorised. Make sure you have authorized My Tax Digital using the Government Gateway account associated with this VRN. If not, click on the MTD VAT Authorization tile to reauthorize."

Hi,

Please contact our VAT team so we can investigate.

VAT: general enquiries

Thank you.

Thanks for the reply. I eventually got through the HMRC Vat team helpline and I have to say they were excellent and very patient. Turns out I was logging into the wrong GOV Gateway account which is bizarre as its the one I always logged into on this machine. My personal one I think. It does let you get all the way through authorisation but at the last minute when you save your VAT number it throws up the error. I think the HMRC support agent said the software had been tightened up to stop this being allowed hence the error.