it’s drm protected and you need keys to decrypt. I already have these two extensions and it’s working.

https://github.com/FoxRefire/wvg/tree/next + https://addons.mozilla.org/en-US/firefox/addon/hls-stream-detector/ or https://github.com/DevLARLEY/WidevineProxy2

https://github.com/nilaoda/N_m3u8DL-RE (downloader and use the keys to decrypt the file)

example mpd “https://vodnowusoawsdash-cf.tvnow.de/pgrn/cves/sd/rtlplus/932203/1-1-1d-3-2-1-2.ism/v1.mpd” (the free trial video only gives me SD)

in .mpd, replace 3-2 with 1-1 to get HD (1080p)