Having trouble displaying Chartboost interstitial ads in my Unity game, getting 'No fill' errors.

The 'No ad content available' error, often referred to as a "no fill" error, is a common headache in mobile app monetization. It essentially means that while your Chartboost SDK is correctly integrated and making a request, the Chartboost ad network could not find an eligible ad to serve at that specific moment for your user, device, or geographic location. This isn't always a direct setup mistake in your Unity code, but it often points to a configuration issue or a lack of inventory for your specific targeting.

Here are the primary areas to investigate when you're facing Chartboost interstitial 'no fill' issues in Unity:

• Chartboost Dashboard Configuration:
  • App Status: Ensure your app is correctly configured and "live" in the Chartboost dashboard, not still in a testing or pending state.
  • Campaigns & Placements: Verify that you have active interstitial campaigns targeting your app. Check the bids and targeting settings for these campaigns. Sometimes, overly restrictive targeting (e.g., specific OS versions, device types, countries) or low bids can lead to zero available inventory.
  • Test Mode: For initial integration and debugging, enable "Test Ads" in your Chartboost dashboard for your app. This guarantees a fill with a test ad, confirming your integration is sound before you worry about live ad inventory. You can also use specific test App IDs/Signatures provided by Chartboost.
• SDK Initialization & Lifecycle:
  • Correct Initialization: Double-check that you are calling Chartboost.StartWithAppId(appId, appSignature); early in your game's lifecycle, ideally once when the app launches.
  • Cache Before Show: Ad networks operate asynchronously. You must call Chartboost.CacheInterstitial(CBLocation.Default); (or your specific placement name) well *before* you intend to show the ad. Then, listen for the DidCacheInterstitial delegate to confirm an ad is ready before calling Chartboost.ShowInterstitial(CBLocation.Default);. Trying to show an ad that hasn't finished caching will result in a 'no fill'.
  • Placement Name Consistency: Ensure the placement name you use in your Unity code (e.g., CBLocation.Default) exactly matches the placement name you've set up in your Chartboost dashboard. Case sensitivity matters.
• Network Connectivity & Device:
  • Internet Connection: Confirm your test device has a stable internet connection. Ad requests fail silently if there's no network.
  • Device Compatibility: While rare, ensure your device and OS version are generally supported by the Chartboost SDK.
• Ad Mediation (Future Step): If you continue to experience low fill rates even after confirming your setup, consider integrating an ad mediation platform. Mediation allows you to route ad requests to multiple ad networks (like Chartboost and alternatives such as Unity Ads, AdMob, AppLovin) to maximize your fill rate and eCPM. This is a common strategy for robust app monetization.

Start with enabling test ads and verifying your dashboard campaign settings. This usually uncovers the root cause for beginners. Hope this helps your conversions!

And you're totally right about the Test Mode in the dashboard, that's a big one I need to go look at first. Definitely gonna confirm my app's setup there.