diff --git a/lib/ads/interstitial_ad_manager.js b/lib/ads/interstitial_ad_manager.js
index 353ad621ab..2b387206ea 100644
--- a/lib/ads/interstitial_ad_manager.js
+++ b/lib/ads/interstitial_ad_manager.js
@@ -665,12 +665,12 @@ shaka.ads.InterstitialAdManager = class {
         const dataAsJson =
         /** @type {!shaka.ads.InterstitialAdManager.AssetsList} */ (
             JSON.parse(data));
-        for (const asset of dataAsJson.ASSETS) {
-          if (asset.URI) {
+        for (const asset of dataAsJson['ASSETS']) {
+          if (asset['URI']) {
             interstitialsAd.push({
               startTime: hlsInterstitial.startTime,
               endTime: hlsInterstitial.endTime,
-              uri: asset.URI,
+              uri: asset['URI'],
               isSkippable,
               canJump,
               resumeOffset,