When trying to Fetch Periods in VAT Filer in some cases you may receive an error message: '500 Internal Server Error'.

HMRC’s guidance on error codes advises that any 500 codes (500 to 599) is an issue from HMRCs server as per the below extract:

Errors

We use standard HTTP status codes to show whether an API request succeeded or not. They are usually in the range:

• 200 to 299 if it succeeded, including code 202 if it was accepted by an API that needs to wait for further action
• 400 to 499 if it failed because of a client error by your application
• 500 to 599 if it failed because of an error on our server

Therefore there is nothing that TaxCalc or any third party service provider can do to assist you with this error. 

HMRC have advised:

Investigations found that this error is returned where the customer has not waited the recommended 72 hours for their record to be migrated to the MTD service. This means when they attempt to call an obligation there is no record for us to return.

We recommend:

• Agents and customers should only attempt to submit a VAT return once they have received the email confirming the customer is now in MTD.
• If, after 72 hours, they are still receiving an error, they should report it to HMRC. (You should use the link for Get help using VAT online services)