There's some interesting commentry at https://www.techtimes.com/articles/322754/20260803/norway-id... , which suggests that the widespread outage is due to a single point of failure:

> ID-Porten: When One Gateway Controls Everything

> At the center of the disruption is ID-porten — the national login gateway operated by Norway's Digitaliseringsdirektoratet (Digdir), the government agency responsible for public-sector digitalization. ID-porten functions as the single sign-on portal through which Norwegian citizens authenticate themselves to access public digital services.

It seems to be a corporate service provider that's a dependency for many other services.