In this thread there was another post linked by the op:
https://lemmy.world/post/6323131
It opens in the browser instead of Boost which is kinda annoying (can’t vote, easily hide comments etc). Is there a way to open it in Boost? I already set all permissions to open Lemmy links in Boost.
The problem is that it's a https link to another instance. Boost would need to know what the corresponding url/post would for your instance to open it properly. Jerboa has the same issue.
You'll notice if you open the link in your browser that you'll be sent to lemmy.world's website, where you aren't logged in.
Use lemmyredirect and you can shunt links to boost.