Some, but not all, agents have been unable to access HMRC online services through the agent portal since Friday 30 November 2018. HMRC had announced that MTD and agent services account services would be closed for scheduled maintenance until 11:00 on 4 December 2018 but this closure was not expected to affect services available through the regular agent portal such as self assessment.
HMRC has not published any information on its service availability page. The issue has been raised on the online agent forum and the Tax Faculty has raised the issue directly with HMRC, including making them aware of the impact at this time of year - a response is awaited.
Agents affected should raise the issue on the forum and email email@example.com. If you have not already joined the forum following the joining instructions.