Here's the Quote Request Mastodon sends me.
https://colours.bots.edent.tel/data/inbox/68d979af-145daa4fe72cf333caba16effb8419ee85f7ed100b15c7ec16b0394629a309bb.json

This is the Stamp my bot generates.
https://colours.bots.edent.tel/quotes/68d979af-3a15-f520-ac6e-13b2d6d96d1b.json

This is the Accept my bot sends Mastodon.
https://colours.bots.edent.tel/quotes/68d979af-aeb1-83c3-a66c-fcb359e1ff90.json

The Mastodon.Social server shows the quote toot. External servers don't.

Please, someone explain what bone-headed mistake I've made.

(Edit: Updated the links)
#ActivityPub #MastodonAPI