Problem with special characters domain?

Hello, activity pub doesn’t seem to work with my website.

My Website is this. It contains a German ü, which seems to be the problem:
https://daswirdmanjawohlnochsagendürfen.de

My fedi-profile:
https://xn--daswirdmanjawohlnochsagendrfen-ufd.de/author/daswird/
https://mastodon.social/@DasWird@daswirdmanjawohlnochsagend%C3%BCrfen.de
User name:
[email protected]
Blog name:
https://xn--daswirdmanjawohlnochsagendrfen-ufd.de/

Can anyone help me with my problem? When I post on my wordpress blog, nothing appears on Mastodon…. Just that one post from October was working for some reason.

• This topic was modified 3 months, 2 weeks ago by desputin.
• This topic was modified 3 months, 2 weeks ago by desputin.

The page I need help with: [log in to see the link]