I am relatively new to QGIS and use version 3.4.11 for a university project of Polish archaeological features.
I am trying to get the "Digital Elevation Model ISOK – Hillshade" WMTS Layer from "https://www.geoportal.gov.pl/uslugi/usluga-przegladania-wmts" working, but when I try to connect via the Data source Manager, it shows the error: "...failed: Host requires authentication". I use "http://mapy.geoportal.gov.pl/wss/service/WMTS/guest/wmts/ISOK_CIEN?SERVICE=WMTS&REQUEST=GetCapabilities" to connect to the server.
It worked very well before, but when I tried to connect today, the error appeared. What could be the problem?