diff --git a/src/routes/services.ts b/src/routes/services.ts
index 78e36b9..4d22b5a 100644
--- a/src/routes/services.ts
+++ b/src/routes/services.ts
@@ -789,7 +789,7 @@ async function proxySocialRequest(req: Request, rest: string, userId: string) {
 }
 
 function artifactExtension(mimeType: string | undefined): string {
-  const normalized = mimeType?.split(";", 1)[0].trim().toLowerCase();
+  const normalized = mimeType?.split(";", 1)[0]?.trim().toLowerCase();
   const extensions: Record<string, string> = {
     "audio/mpeg": "mp3",
     "audio/mp3": "mp3",