Interop with Bridgy Fed, failed inbox delivery of reply to Misskey

Hi! Bridgy Fed has fairly mature ActivityPub support, it's been interoperating with other established AP implementations for years, so I'm hoping to get it to interoperate with Misskey too.

As a test, I used it to post a reply to this original post on slippy.xyz, running Misskey 13.13.0. Bridgy Fed delivered the activity below to https://slippy.xyz/users/85l270n95u/inbox , including an HTTP Signature from the sending actor, at 04:45:59 UTC 2-23-06-05. slippy.xyz responded HTTP 202, but the reply hasn't shown up yet, so I expect background processing of the activity failed.

Thanks in advance for looking, let me know if I can do anything to help!

(Also tracked in https://github.com/snarfed/bridgy-fed/issues/375 )

{
  "id": "https://fed.brid.gy/r/https://snarfed.org/2023-06-05_gitea_blog_bot-slippy-2#bridgy-fed-create",
  "actor": "https://fed.brid.gy/snarfed.org",
  "@context": "https://www.w3.org/ns/activitystreams",
  "type": "Create",
  "object": {
    "published": "2023-06-05T21:45:52-07:00",
    "content": "<a class=\"u-in-reply-to\" href=\"https://slippy.xyz/notes/9a484gym1e\"></a>\n<div class=\"e-content\">\ncongrats!\n</div>",
    "url": "https://fed.brid.gy/r/https://snarfed.org/2023-06-05_gitea_blog_bot-slippy-2",
    "type": "Note",
    "attributedTo": {
      "url": "https://fed.brid.gy/r/https://snarfed.org/",
      "image": {
        "url": "https://secure.gravatar.com/avatar/947b5f3f323da0ef785b6f02d9c265d6?s=96&d=blank&r=g",
        "type": "Image"
      },
      "type": "Person",
      "name": "Ryan Barrett",
      "icon": {
        "url": "https://secure.gravatar.com/avatar/947b5f3f323da0ef785b6f02d9c265d6?s=96&d=blank&r=g",
        "type": "Image"
      },
      "id": "https://fed.brid.gy/snarfed.org",
      "preferredUsername": "snarfed.org"
    },
    "inReplyTo": "https://slippy.xyz/notes/9a484gym1e",
    "id": "https://fed.brid.gy/r/https://snarfed.org/2023-06-05_gitea_blog_bot-slippy-2",
    "cc": [
      "https://slippy.xyz/users/85l270n95u",
      "https://slippy.xyz/users/85l270n95u/followers",
      "https://www.w3.org/ns/activitystreams#Public"
    ],
    "tag": [
      {
        "type": "Mention",
        "href": "https://slippy.xyz/users/85l270n95u"
      }
    ],
    "to": [
      "https://www.w3.org/ns/activitystreams#Public"
    ]
  },
  "to": [
    "https://www.w3.org/ns/activitystreams#Public"
  ]
}

misskey-dev / misskey

Interop with Bridgy Fed, failed inbox delivery of reply to Misskey #10963