This error/issue is from HMRC's side and is not something Access are able to assist with.
To learn more on this, please review the sources below which would be kept updated by HMRC. Please note, HMRC may delay at times to update these.
https://api-platform-status.production.tax.service.gov.uk/incidents
https://www.gov.uk/government/publications/making-tax-digital-for-vat-service-availability-and-issues/making-tax-digital-for-vat-service-availability-and-issues
Error - 'Unable to retrieve your unfulfilled obligations. Please close the error message to retry. HMRC service currently available' Unable to submit to HMRC
Updated this week