Hello Sarah, thanks for reaching out about the MTD connection. The error you receiving could be a few things.

*It could be the VAT number in QB does not match HMRC records.

*Or that the gateway information is incorrect in QB.

So if you could check those.

If they are both correct if you can disconnect and then reconnect the MTD connection.

We've included a help article here, no.6 on the article is the error you are receiving and it has the steps in more detail to resolve.

Any questions ot if you receive the same issue after trying the above, let us know.

Thanks.