diff --git a/CHANGELOG.md b/CHANGELOG.md
index 155248a81..0dc536c55 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -32,6 +32,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Remote users can no longer reappear after being deleted.
 - Deactivated users may now be deleted.
 - Mix task `pleroma.database prune_objects`
+- Fixed rendering of JSON errors on ActivityPub endpoints.
 - Linkify: Parsing crash with URLs ending in unbalanced closed paren, no path separator, and no query parameters
 
 ### Removed
diff --git a/config/config.exs b/config/config.exs
index 2f8a18788..b50c910b1 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -460,7 +460,7 @@
   enabled: true,
   limit: 5_000
 
-config :phoenix, :format_encoders, json: Jason
+config :phoenix, :format_encoders, json: Jason, "activity+json": Jason
 
 config :phoenix, :json_library, Jason