You need to change the format of the links for them to work for people on other instances: the link needs to be only /c/communityname@lemmynsfw.com, I think. Testing that theory:

!porn@lemmynsfw.com

And it looks like this one works for me as someone on another instance whereas your links take me away from my instance

For some reason the autofill function in Lemmy does not do links this way automatically