diff --git a/src/main.ts b/src/main.ts
index cf9ab38..8ba0119 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -26,7 +26,7 @@ async function run() {
     );
     console.log(`Replaced tokens in files: ${result}`);
   } catch (error) {
-    core.setFailed(error.message);
+    if (error instanceof Error) core.setFailed(error.message);
   }
 }