lemmy.pt apprears to be federated with blahaj.zone, and vice versa, and lemmy.pt is even on a newer version of lemmy than blahaj.zone, so my guess is there are issues with federation for various reasons, who knows what.

Could be federation issues as mentioned, however I would double check your language settings to ensure you’re not hiding posts in Portuguese, though I would still expect some posts that don’t have the correct language / are in English to show (and undefined).

The way federation works is that content from remote communities doesn’t federate here until one of our users subscribes to it. You made your post about a week ago, but you made it in reply to a 2 year old post on a remote community, and that community has not had any activity at all, here or on its home instance, in over 3 months.

If you are subscribed to that community now though, any future posts that get made to it will federate to us and you’ll be able to interact with it. On the lemmy.pt instance, even their most active and subscribed community hasn’t had any posts made to it for over 2 weeks, so if you subscribed to it after that, none of their content will have federated to us yet.

But, if you make a brand new post in one of their communities, everyone else on lemmy that is subscribe to that community will be able to see it and reply to it.

tl;dr - Federation means that existing content in old, low volume communities don’t federate very well if you’re the first subscriber on our instance. But once subscribed, it will work fine for future content.

Edit - Also, as others have said, check your language settings. You want to make sure that in your settings you have English, “Undetermined” and Portuguese selected (as well as any other languages you speak). If you don’t select the language in your settings, lemmy hides all content tagged with that language from you. And if you don’t select undetermined, lemmy hides all of the content that people haven’t set a language tag for at all (which is most lemmy content)