It was
https://playground.bonfire.cafe/post/01G6Z11G4JE5GF3B12QFXTBV57#activity-01G6Z15PZ06NB4003Q7SFKD2Y3
But other attempts to REPLY and WRITE have failed with seemingly the same error. The common factor may have been refeences outside th Bonfire playground sandbox. Like, to fediverse identitites like Bonfire AT indeweb.
Don't have more time to diagnose, apologies, must go.
Cool campfire vibes! 😁 (Illustration Moomins by Tove Marika Jansson)