Datafordeleren’s web services (wms., wmts., wfs., wcs.datafordeler.dk) need an API key, sent as the apikey query parameter. The older username/password access is retired.
Get a key: follow Brugeradgang (free): create a user in Datafordeleren’s Administration (with MitID Erhverv or an e-mail address), create an IT system there, and give it an API key.
See Datafordeleren and its registers and services.