Client App SDK 4.1.0 - postMessage failing with "Invalid Target Origin

General Discussion
1

We’re hitting an issue after upgrading to the Client App SDK v4.1.0 - was on 4.0.2 previously. postMessage calls to the embedded frame are now failing with “Invalid Target Origin” - it’s consistently happening with screen pops. The documentation says the origin check “prevents malicious websites from accessing the embedded application’s data” but it was working fine before the upgrade, and the target origin hasn’t changed.

It looks like the SDK is now stricter about validating the origin - which, okay. Still.

Here’s what we’ve checked:

  • SDK version: 4.1.0
  • GC Environment: Production
  • Flow Configuration: The screen pop flow uses the “Open URL in new tab” action.
  • Target Origin: The embedded application’s origin is set correctly in the GC configuration - we’ve verified this.
  • INC-4471: We previously saw similar behavior with a different SDK version, and the resolution was updating the CORS policy - doesn’t look like that’s the issue this time.
  • Console logs: The error is DOMException: Invalid Target Origin in the browser console.

The postMessage call looks like this:

parent.postMessage({
 type: 'screenPop',
 data: {
 url: 'https://our-embedded-app.com/some-resource'
 }
}, 'https://our-embedded-app.com');

Side note - the documentation doesn’t really cover this scenario. Change in SDK version → origin check failing.

1 Like
2 
{
 "targetOrigin": "https://your-domain.com"
}

We had a similar case last month - someone in the community found that the targetOrigin in the postMessage call must match exactly the domain of the embedded frame. It’s a quick one - check the domain setting in your client app configuration.

3

That fix worked - we had a typo in the target origin setting in the client app config, it was pointing to the wrong subdomain. Changing it resolved the “Invalid Target Origin” error immediately. We also saw this reported internally in INC-4471, so we’ll update our upgrade notes.

2 Likes
4

That’s right, confirming the targetOrigin is key - it’s like ensuring your GPS has the correct destination entered, or you’ll end up somewhere unexpected. The documentation notes, quote, “The targetOrigin must match the origin of the iframe exactly” - even a slightly off subdomain will cause issues. Just double-check it’s a fully qualified domain name too.

5

That’s right, the targetOrigin needs to be spot-on - it’s a security thing, the browser won’t let the message through if the origins don’t match. PureCloudPlatformClientV2 is doing what it should there, being careful about cross-origin communication. One gotcha I ran into last year - and it took way too long to find - is that the origin check is case-sensitive. We had https://SubDomain.YourDomain.com in the client app config, but the iframe was loading from https://subdomain.yourdomain.com - different origin as far as the browser’s concerned. Not 100% sure if that’s what happened here, but it’s worth a look. It’s a small thing that causes a massive headache.