The reasons why you are unable to connect Easy MTD with HMRC are listed below:
- You did not specify the Government Gateway credentials (user ID and password) for the business you have specified in Easy MTD - e.g. you specified credentials for your personal HMRC account. Often, credentials previously used to sign in to the Government Gateway are saved by your browser so ensure they match those of your HMRC business account.
- You have previously signed up and used GOV.UK One Login, and did not choose that option when asked to sign in to HMRC.
- The wrong VAT number is specified for the business in Easy MTD.
- If you are an agent, you did not specify your agent services account credentials.
- You are running Easy MTD in "sandbox" mode. Check the Easy MTD title bar for "(Sandbox)" and if it is visible, contact us for details about how to disable "sandbox" mode.
- The HMRC system is unavailable due to maintenance or a problem.
- There is an issue with your HMRC account that may have been caused by the recent introduction of GOV.UK One Login, or something else caused by HMRC.
If you continue to experience a problem connecting Easy MTD with HMRC, please contact HMRC (use the link below) so they can check whether your HMRC account is problematic or to advise on whether you should use the Government Gateway or GOV.UK One Login during the connection process. Please also consider that the connection process used by Easy MTD is the same process used by all Making Tax Digital solutions. Therefore, if you are unable to successfully connect using Easy MTD, you will be unable to do so using another solution.
https://www.gov.uk/government/organisations/hm-revenue-customs/contact/vat-enquiries
More: For further details about connecting Easy MTD with HMRC, refer to the Connecting with HMRC section of the help.