It is a Lemmy problem, as I sometimes need to retry even on the web. Or, rather, a problem with the servers of some instances buckling under the weight of the huge influx of new users in the past few days. Still things are clearly becoming better (thanks for your effort, admins!) and will sort themselves out in time.
It’s more specifically a Lemmy.world problem, the servers are overwhelmed. Try a smaller instance like Lemm.ee (or countless others). You still see the same feeds but everything runs much smoother.
it is a lemmy.world problem because the server cannot currently handle the sheer amount of new users and posts. i notice that it's gotten a lot better today in comparison to the last few days. i'm too lazy to make a new account and subscribe to my current list of communities again, so i'm just waiting it out. you can make a new account on a less populated instance and you should be fine.