[Symbiote]

The OP wrote that Deutsch Post (probably) or Posten (possibly) messed it up.

The Germans messing it up seems much more likely. There are plenty of Norwegian addresses containing Å/Æ/Ø.

[kergonath]

Yeah but that does not make any sense. Deutsche Post would not have changed the label so the address would still be correct.

[Symbiote]

I have no idea why you think it's inconceivable that Deutsche Post wouldn't corrupt the label, but Posten (Norwegian Post), who actually use the letter Å, would have.