diff --git a/backend/src/middlewares/auth.ts b/backend/src/middlewares/auth.ts
index c862344af..d833413c8 100644
--- a/backend/src/middlewares/auth.ts
+++ b/backend/src/middlewares/auth.ts
@@ -186,10 +186,16 @@ async function authenticateWithBearerToken(
       );
     } else if (errorCode?.includes("auth/user-not-found")) {
       throw new MonkeyError(
-        401,
+        404,
         "User not found.",
         "authenticateWithBearerToken"
       );
+    } else if (errorCode?.includes("auth/argument-error")) {
+      throw new MonkeyError(
+        400,
+        "Incorrect Bearer token format.",
+        "authenticateWithBearerToken"
+      );
     } else {
       throw error;
     }