MTD Quarterly Filer - known errors

From initial testing we have established the following issues when setting up/submitting quarterly updates:

HMRC error '403 Client or Agent Not Authorised' when trying to link the business

This is usually because the client is not registered for MTD, the agent does not have an Agent Services Account or the client has authorised the agent to act on their behalf. Individuals should check their government gateway accounts to ensure they are registered for MTD (or start the registration process). Agents should ensure they are using the Agent Services Account credentials (and not Government Gateway credentials) and ensure the client can be seen as authorised and signed up for MTD on their Agent Services Account.

Quarterly Statuses - not all periods retrieved from HMRC

After amending to 'Calendar' option in Business Information, when clicking 'Refresh HMRC statuses', potentially not all obligation periods will be retrieved. This is because of a delay in HMRC systems changing the obligation period dates. Clicking 'Refresh HMRC statuses' again later should retrieve all four periods.

HMRC error 'Matching Resource Not Found' when submitting an update period

This suggests that HMRC do not recognise the business ID. We suggest calling HMRC on the pilot customer helpline that would have been provided when registering the client for the pilot scheme. This message will also appear if the 2026/27 tax year has been signed up for but a submission has been tried for 2025/26. HMRC will be able to correct the year in their system from 15 December 2025, after a system update.

HMRC error 'Rule Start Date Not Aligned with reporting type' when submitting an update period

If an election to submit 'Calendar' quarters was made but then changed to 'Standard' (by HMRC changing the business record on their system), firstly ensure that 'Refresh HMRC statuses' (found in Quarterly Statuses) has been clicked so that the obligation periods reflect the correct start and end dates.

If the first obligation period was submitted with a start date of 1 April (to overcome the error) then subsequent obligation periods should also be submitted with a start date of 1 April.

If this has been done and the error still occurs, it will probably be related to an HMRC's system not recognising the change in reporting type. We suggest calling HMRC on the pilot customer helpline that would have been provided when registering the client for the pilot scheme.

Response error when fetching obligations

This error can occur when  a period has been created in Quarterly Filer which does not match the MTD period signed up for with HMRC. Unlinking the business, deleting the period and recreating the correct period, then re-linking the business in Quarterly Filer will usually resolve this issue.

Connection error when trying to authorise TaxCalc to connect to HMRC

This is caused by the system environment blocking access to HMRC server. We recommend contacting your IT support/hosted team and ask them to try excluding the sites in the below knowledgebase article from the proxy server to see if this helps (if not already done):

Excluding sites from Proxy Server checking

And to also try excluding the below site from the proxy server:

api.service.hmrc.gov.uk (used by MTD APIs)

Then can a user trying authorising to HMRC again in TaxCalc to see if it then works.

HMRC error when trying to submit an period to HMRC for the quarter.

This appears to be due to a connection interruption with HMRC. If you do receive this message, please contact TaxCalc Support quoting the case reference PROD-16034 so we can keep a track of these instances to investigate further.