What is it and I’ll tell you what the signs would be to me, but that instance went a way months ago.
My instance must have never cached it. Can’t see it.
I can see 3 month old posts there. Nothing new.
And I've been posting 1/day for the last week or so.
I see your posts. From oct 28th
You're on lemm.ee, just like me. I think that's the key.
You can see that an instance/community is gone by visiting the instance directly. In this case at https://lemmy.fmhy.ml/c/imaginarymechas (which obviously won't work now, as it's gone).
Whenever you submit a post to a community, first your own instance saves the post locally, then sends it to the instance hosting the community, this instance then sends it to any other instance with users subscribed to the community. When the hosting instance is down, then that step of course fails, resulting in the post being only visible to members of your own instance.
That's how I ended up realizing it. Someone told me it was down, so I went to it directly and found that. I wouldn't have noticed that if someone hadn't told me. This seems like a bug, to me.
I'm not sure I'd classify it as a bug. Instances can temporarily go down at any moment for numerous reasons, to account for this instances will keep retrying to connect with an exponential backoff. At what point should an instance assume that another instance is permanently gone?
Perhaps a good start would be adding a status indicator to every community with something like last sync: 1 minute ago.
That sounds good. Once it passes a threshold, you can assume something serious is wrong.
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