Gremlins that showed up during a planned upgrade to the Department of Work and Pensions systems brought down online services for more than 24 hours, sources have told The Register.
Techies at the services-based reseller SCC, which has a hosting contract with the DWP, began the work yesterday but some unspecified difficulties emerged.
Engineers tried to roll back the upgrade but it proved too complicated so they carried on overnight, we are told.
The systems were down from mid-morning yesterday until around 2pm this afternoon which impacted access to sites, and prevented Joe Public from accessing app and the Universal Credit portal.
The portal had stated: Sorry for the inconvenience, we re just making some improvement to help make your online experience better.
You ll be able to access your online account again shortly .