Have connect to HMRC for MTD, works fine onclients, except one, where it does not think I have connected - based on QB , the single connection should cover all clients

Thanks for posting here, michelle43.

Let's make sure that you've linked your client to your ASA for MTD services. You'll have to complete the steps on HMRC website to set up your clients and QuickBooks. Please refer to this article the detailed guide: Setting up MTD-eligible clients on HMRC and QuickBooks - MTD for accountants.

If you have done these steps, please reach out to our Customer Support Team. They can check why you're client isn't connected to HMRC.

1. Go to Help and select Contact Us.
2. Enter Connect to HMRC in the question field, then select Let's talk.
3. Choose either Chat or Get a callback.

For reference, you can also read this article: Connect QuickBooks to HMRC to submit VAT - MTD for accountants.

Please reply to this thread if you have more concerns. I'll be here!