VAT certificate amended and now I can access online account or MTD

Sent a change of details to the HRMC a few months ago and received a letter back last week saying changes had been approved and an amended certificate was issued. Tried to submit my Vat return for August-October yesterday and Quickbooks said there was a problem and couldn't submit it. Went to my online tax account and while I signed in okay nothing on the page works. It says 'temporarily unable to display VAT return details' and when i click on anyhting it says 'Sorry, there is a problem with this service.' Do i need to set up a new Government gateway for the amended VAT registration (Number is still the same) , or do i need new MTD log in details.? Any help would be appreciated.

Hi,

Please contact our VAT team so that we can open up your online account and resolve any issues.

Contact details can be found here:

VAT: general enquiries

Thank you.