diff --git a/extensions/matrix/src/matrix/send.ts b/extensions/matrix/src/matrix/send.ts
index 86c703b93de..6aea822f882 100644
--- a/extensions/matrix/src/matrix/send.ts
+++ b/extensions/matrix/src/matrix/send.ts
@@ -92,7 +92,7 @@ export async function sendMessageMatrix(
           buffer: media.buffer,
           contentType: media.contentType,
           fileName: media.fileName,
-          kind: media.kind,
+          kind: media.kind ?? "unknown",
         });
         const baseMsgType = resolveMatrixMsgType(media.contentType, media.fileName);
         const { useVoice } = resolveMatrixVoiceDecision({