You are not misrembering. They announced it at the beginning of this month [0][1] and have officially shut down all of their hosted instances as of about a week ago [2]

[0] https://cadence.moe/blog/2022-09-01-discontinuing-bibliogram

[1] https://news.ycombinator.com/item?id=32683722

[2] https://git.sr.ht/~cadence/bibliogram-docs/tree/master/docs/...