Cubase 15 Pro Error: Service "mediaserver 0_9_3" not registered

​I’m running Windows 11 and I’m completely stuck with an issue in Cubase 15 Pro.

Every time I open the software, I get this exact error pop up:
​Service “mediaserver 0_9_3” not registered.

The software seems to open but when I try to open instruments like Groove Agent, HALION Sonic, etc… I notice that all the sound libraries/presets are completely empty.
​I tried searching online for a solution and saw suggestions to reinstall the MediaBay via the Steinberg Download Assistant, but I can’t find any separate option or file for MediaBay in the Download Assistant.
​Does anyone know how to properly fix this registration error or where to find the standalone MediaBay installer?

Near the top.