I (@lemmy.world) am just trying (barely) to interact with Mastodon instances (posts and comments)

@lemmy.world website,

1. I can see Mastodon user's profile but no posts and comments displayed.
2. Yet, Mastodon users can comment/reply to Lemmy posts and comments.

@mastodon.social website,

1. Some of my (@lemmy.world) posts & comments in a profile at mastodon.social don't appear.

I just hope I can finally "converse" with Mastodon users and other users from "non-Lemmy" instances such as misskey, calckey and others (of course function of ActivityHub and dream goal of Fediverse).