‘solved’ was a fallacy. Currently, it puzzlingly fails with requests such as:
(request-target): post /user/1/inbox.json
host: gnusocial.net
date: Thu, 21 Jul 2022 10:19:19 GMT
digest: SHA-256=olrkFelf87xqs/N2gg2Vlmd3s0ns7l47tPSQipyrYxs=
content-type: application/activity+json
signature: keyId="https://demo.mro.name/seppo/activitypub/#main-key",algorithm="rsa-sha256",headers="(request-target) host date digest content-type",signature="gGbfGZqVMT/Md8ix3/25l+jULXps2PfRQtr7S+t4QyV0Ubi6JBk+qHgej0GOJ0R/5jAWy0hRA7jmF0g/VIvCcWf9TdnSNFXmDc7q5dkzl7wwaRm+ER8UkiqC+y4f80RNa8Xer/cPD2z0zMe7bg8xSTTSwZOq3jf/N1y1VjaysRlcX+qgBTjNEzGy5RLetaeibxg+80LcioVPfu9QL5lHw2U+959wXxzqZx3r8Tv1ggqOGi2+WuFC6X4fTdh49+KdCw7tyHpKnIyzQ19WehqFvLQqesKS/T0OCiRmgKOsemwfIzLTU91W94pcPJnY3fJ2zjySpqj17TbUdLp3JoTwyw=="
Accept: application/activity+json
User-Agent: Seppo/0.1
{"type":"Like","@context":"https://www.w3.org/ns/activitystreams","id":"https://demo.mro.name/seppo/activitypub/likes.json#https://gnusocial.net/notice/11921862","summary":"That's the way, aha, aha, I Like it.","published":"2022-07-21T10:19:19-00:00","actor":"https://demo.mro.name/seppo/activitypub/","to":["https://gnusocial.net/index.php/user/1"],"cc":["https://www.w3.org/ns/activitystreams#Public"],"object":"https://gnusocial.net/notice/11921862"}
Have opened https://notabug.org/diogo/gnu-social/issues/287 but peertube, mastodon, lemmy, pleroma, pixelfed fail likewise. Some without response, some with ‘ok’, some with ‘500’, some with ‘403’.