Question about FRITZ! Box 5590 Fibre XGS-PON

Unfortunately not. At least I couldn't get it to work after many calls to Sunrise.

Ask Sunrise whether this Fritzbox is on the "blacklist".

I have not yet put it into operation

but it works, even flawlessly ;) just needs to be set correctly, will be more specific as soon as I get home

I couldn't manage it either. Unfortunately.

Unfortunately not, Sunrise does not support it.