diff --git a/data/api/server-server/events.yaml b/data/api/server-server/events.yaml
index 9087df97..620e1924 100644
--- a/data/api/server-server/events.yaml
+++ b/data/api/server-server/events.yaml
@@ -140,6 +140,19 @@ paths:
                 required:
                   - auth_chain_ids
                   - pdu_ids
+        "403":
+          description: |-
+            The host is not in the room or the host is banned from the room via its ACL.
+          content:
+            application/json:
+              schema:
+                $ref: ../client-server/definitions/errors/error.yaml
+              examples:
+                response:
+                  value: {
+                    "errcode": "M_FORBIDDEN",
+                    "error": "You do not have permission to access the state at the requested event."
+                  }
         "404":
           description: |-
             The given `event_id` was not found or the server doesn't know about the state at