diff --git a/packages/backend/src/server/api/mastodon/middleware/catch-errors.ts b/packages/backend/src/server/api/mastodon/middleware/catch-errors.ts
index 4019e2c6c..b843a6fb5 100644
--- a/packages/backend/src/server/api/mastodon/middleware/catch-errors.ts
+++ b/packages/backend/src/server/api/mastodon/middleware/catch-errors.ts
@@ -28,6 +28,7 @@ export async function CatchErrorsMiddleware(ctx: MastoContext, next: () => Promi
         if (e instanceof MastoApiError) {
             ctx.status = e.statusCode;
         } else if (e instanceof IdentifiableError) {
+            if (e.message.length < 1) e.message = e.id;
             ctx.status = 400;
         } else if (e instanceof ApiError) {
             ctx.status = e.httpStatusCode ?? 500;