Hi there! Looks like you linked to a Lemmy community using a URL instead of its name, which doesn't work well for people on different instances. Try fixing it like this: !asklemmy@lemmy.ml,
You didn't type @Magrid@lemm.ee though, you started typing and selected the dropdown box link. This creates a direct link to the user's instance, which isn't great.
If you type /u/username@instance then you will get an instance agnostic link, which will be in the viewer's instance. Eg /u/UnanimousStargazer@feddit.nl - if you click View Source then you will see I did not type a link, yet when you hover over it the URL (for you) is https://lemm.ee/u/UnanimousStargazer@feddit.nl. With an instance agnostic link you stay in your instance and see a federated version of the user's page, which allows you to do things like message them.
Edit: I don't see a link when using this method on Voyager or Jerboa, whereas @TWeaK@lemm.ee does work. It seems Lemmy apps don't support your way of doing it yet.
Yeah, really they should all function the same way. /u/ should give a mention, and typing @user@instance should automatically create a link - without the dropdown box or full link code.