Troubleshooting

The ad doesn't show

Follow the flowchart from top to bottom — it leads from the first event to the cause.

Symptoms and causes

Symptom	Cause	Solution
No events at all	The Android interface or AdEventsHandler handler isn't registered	Check the name — it's case-sensitive.
Android: one event doesn't arrive	The method's argument count doesn't match the signature	Check the signature table.
AdError 1	The address has no url, or controls isn't valid JSON	Encode the parameters with encodeURIComponent.
AdError 303	The ad server didn't return an ad	This is normal — return to the content.
AdError 901	The VPAID creative got a zero screen size	Make the WebView visible before the ad loads.
AdError viewport_unavailable	The page has no dimensions for 3 seconds	The WebView must be visible and sized.
Buttons are visible, no ad	The WebView background isn't transparent, or the WebView is below the player	See How the SDK works.
No quartiles or AdComplete	timeupdateAd() isn't being called	Call it on every player position update.
No AdComplete at the end	timeupdateAd(duration, duration) wasn't called	Call it when the player finishes the ad.
The skip button doesn't become active	Time isn't arriving via timeupdateAd()	Same as above.
Browser: permission_denied	The browser blocked autoplay with sound	Start playback after a user action, or without sound.

How to debug

Enable debug output

Add &debug=true to the page address — the SDK will start writing debug messages to the console.

Connect an inspector

• Android: WebView.setWebContentsDebuggingEnabled(true), then chrome://inspect in Chrome on your computer.
• iOS: webView.isInspectable = true (iOS 16.4+), then the Develop menu in Safari.

Compare with the Playground

Open the Playground, select the same platform, and paste in your VAST link. If events arrive there but not in your app, the problem is in the integration, not the ad tag.