fixed issue #246

Former-commit-id: 7cca2d602c2d5fcc6a435e02de409f63976678de

lib/hooks/content/content-hooks-web.js

@@ -51,7 +51,7 @@
 			const response = await fetch(url, { cache: "force-cache" });
 			detail = { url, response: await response.arrayBuffer(), headers: response.headers, status: response.status };
 		} catch (error) {
-			detail = { url, error };
+			detail = { url, error: error.toString() };
 		}
 		dispatchEvent(new CustomEvent(FETCH_RESPONSE__EVENT, { detail }));
 	});