You can check for any instance who they have federated with and who they have blocked by navigating to their /instances page.
For example for Beehaw: https://beehaw.org/instances
I think it just means their server is having some trouble serving requests 😅
That's a public URL on Beehaw side, so whenever you open that URL, they'll actually have no way of knowing what your home instance is what its federation status is.