MTD HMRC Connection Not Authorised: How to Fix It

If your MTD software says HMRC has not authorised the connection, the problem is usually not your spreadsheet. The refusal happens before any quarterly figures are imported or submitted.

You may also see an error such as CLIENT_OR_AGENT_NOT_AUTHORISED. That message means HMRC has not authorised the account and taxpayer details for the requested Making Tax Digital service. Work through these checks in order.

1. Check that you signed up for MTD for Income Tax

A Self Assessment account on its own is not enough. MTD for Income Tax has a separate HMRC sign-up process.

Sign in to HMRC and confirm that you completed MTD registration for the correct starting tax year and included the relevant self-employment or property sources. If you only started the process, wait until HMRC confirms it is complete before reconnecting your software.

Use HMRC's current MTD sign-up service.

2. Use the same Government Gateway account

HMRC says individuals should authorise software using the user ID and password used when they signed up for MTD for Income Tax. People can accumulate more than one Government Gateway account, so a login that works for another tax service may still be the wrong one for MTD.

Do not send your Government Gateway credentials to Flonancial or anyone else. Enter them only on HMRC's own sign-in page.

3. Check that the taxpayer details match

The National Insurance number stored in Flonancial must belong to the same person as the Government Gateway account being authorised. A typing error, an old account or another person's credentials will stop the match.

Check the value in your Flonancial settings carefully. Never email the full number to support. If support needs to investigate, the account email and attempt time are enough to locate the protected logs.

4. Use the right journey for an individual or agent

Flonancial's current live journey is for a taxpayer connecting their own personal Government Gateway account. It does not currently provide an agent filing portal.

An accountant acting as an agent needs software that supports the HMRC agent-services authorisation route. Using an agent login in an individual flow, or a personal login in an agent flow, will not create the correct authority.

5. Complete HMRC's permission screen

During connection, HMRC asks you to grant the software permission. Closing the tab, pressing back or declining permission means the software does not receive a usable authorisation.

Start the connection again, finish the HMRC screens and let HMRC return you to Flonancial.

6. Reconnect once, not repeatedly

If you have corrected the sign-up or account details, reconnect once and allow the dashboard to finish checking for businesses. Rapid repeated attempts do not fix an HMRC enrolment mismatch and can make the support history harder to interpret.

If HMRC has just authorised the account but Flonancial says it is still finishing the connection, wait a few minutes and refresh once.

7. Contact support with safe, useful information

If the message remains, email Flonancial with:

• the email address used for the Flonancial account;
• the approximate date and time of the latest attempt;
• the exact message shown on screen; and
• whether you are connecting as the taxpayer or trying to act as an agent.

Do not include a Government Gateway password, full National Insurance number, passport image or other identity documents.

If you live outside the UK

Living abroad does not automatically prevent an MTD connection. HMRC says a person who is resident or domiciled outside the UK may still need to follow MTD rules for qualifying UK self-employment or property income.

The same account checks still apply. Make sure the UK income source is present in HMRC's MTD service and that you are authorising the Government Gateway account linked to it.

The short version

1. Complete the separate MTD for Income Tax sign-up.
2. Use the same Government Gateway account used for that sign-up.
3. Check that the taxpayer details match.
4. Use a personal journey for your own filing, not an agent login.
5. Grant permission and let HMRC return you to Flonancial.
6. Reconnect once and wait for the check to finish.
7. Contact support with the error and time if it still fails.

HMRC's software-authorisation guide confirms that the MTD sign-up, Government Gateway credentials and software permission all need to line up.