I'm having difficulty in connecting to MTD and am receiving an error code: error code CLIENT_OR_AGENT_NOT_AUTHORISED

I feel I'm missing something simple here but just can't see it.

We use one government gateway ID for all the existing business aspect such as payroll and self assessment etc. plus we have just set up  a new Government gateway account to re register for VAT and now have a new vat account and can see our certificate online. 

We have also registered at HMRC for MTD and received our confirmation e-mail this morning, but when I look at the VAT page on QBO I get 'We can't connect to HMRC right now' and the green button saying 'Take Action'.  

Any help much appreciated please.

Thank

Andy