diff --git a/demo/.eslintrc.js b/demo/.eslintrc.js
index b6d8111d43..1995e1ad3b 100644
--- a/demo/.eslintrc.js
+++ b/demo/.eslintrc.js
@@ -33,6 +33,16 @@ module.exports = {
   },
 
   rules: {
+    "@typescript-eslint/no-unused-vars": [
+      "error",
+      {
+        args: "all",
+        argsIgnorePattern: "^_",
+        caughtErrors: "none",
+        destructuredArrayIgnorePattern: "^_",
+        varsIgnorePattern: "^_",
+      },
+    ],
     "comma-dangle": [1, "only-multiline"],
     "no-cond-assign": 0,
     "no-console": 1,
@@ -70,13 +80,6 @@ module.exports = {
     "no-case-declarations": 0,
     "no-var": 1,
     "prefer-const": 1,
-    "@typescript-eslint/quotes": [
-      "error",
-      "double",
-      {
-        avoidEscape: true,
-      },
-    ],
     "linebreak-style": [1, "unix"],
     semi: [1, "always"],
     "react/jsx-uses-vars": [2],
diff --git a/demo/scripts/lib/parseDRMConfigurations.ts b/demo/scripts/lib/parseDRMConfigurations.ts
index cd219c720b..de91fcfa26 100644
--- a/demo/scripts/lib/parseDRMConfigurations.ts
+++ b/demo/scripts/lib/parseDRMConfigurations.ts
@@ -55,11 +55,11 @@ function getServerCertificate(url: string): Promise<ArrayBuffer> {
         const serverCertificate = xhr.response as ArrayBuffer;
         resolve(serverCertificate);
       } else {
-        reject();
+        reject(new Error("Could not fetch serverCertificate: HTTP Status Error"));
       }
     };
-    xhr.onerror = (err) => {
-      reject(err);
+    xhr.onerror = () => {
+      reject(new Error("Could not fetch serverCertificate: Request Error"));
     };
     xhr.send();
   });