Failed to execute postMessage Browser Origin: On your device Last updated 15 Oct 2026

Console: Failed to execute 'postMessage' on 'DOMWindow': The target origin provided ('https://a.com') does not match the recipient window's origin ('https://b.com')

window.postMessage() was sent with a targetOrigin that differs from the receiving window's real origin, so the message is dropped.

Exact message you may see Failed to execute 'postMessage' on 'DOMWindow'The target origin provided does not match the recipient window's originFailed to execute 'postMessage' on 'Window'Unable to post message to
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Seen on: Chrome Firefox Safari JavaScript

Meaning

postMessage(data, targetOrigin) delivers only if the receiver's origin equals targetOrigin. Frames that redirect, use www/non-www, http vs https, or different ports will not match. Use the exact origin of the receiving frame (never "*" for sensitive data) and check event.origin on the receiving side.

Common causes

  • Wrong scheme, host or port in targetOrigin (http vs https, www vs non-www)
  • Iframe navigated or redirected to another origin
  • Sending before the iframe has loaded
  • Using window.location.origin for a cross-site recipient
  • Popup closed or replaced

⚡ Quick fix

  1. Send to the receiver's exact origin (read it from the iframe src or a handshake message)
  2. Wait for the iframe load event before posting
  3. Validate event.origin and the message format when receiving

Detailed fix by platform

JavaScript

  1. Sender: iframe.contentWindow.postMessage({type:'init'}, 'https://widget.example.com'); Receiver: addEventListener('message', e => { if (e.origin !== 'https://app.example.com') return; /* ... */ });

How to diagnose

  1. Origins — Sender target vs receiver actual origin?
  2. Redirects — Did the frame redirect?
  3. Timing — Frame loaded?

🔧 Still not fixed?

Many errors look alike. If the steps above didn’t solve it, one of these is probably what you’re facing:

Where this error sits

Origin: On your device. Errors that are often confused with or caused by this one (click to open):

Aw, Snap! — Chrome: Aw, Snap! Something went wrong while displaying this webpage. Error code: STATUS_ACCESS_VIOLATION / SIGILL / Out of Memory (Browser)Aw, Snap!blocked a frame — SecurityError: Blocked a frame with origin "x" from accessing a cross-origin frame. (JavaScript)blocked a framecaptive portal — Browser: This network requires you to sign in — captive portal (hotel, airport, café Wi-Fi) blocking HTTPS sites (Browser)captive portalPermissions policy violation — Console: [Violation] Permissions policy violation: camera is not allowed in this document (Feature-Policy) (Browser)Permissions policy vi…Refused to display in a frame — Console: Refused to display 'https://…' in a frame because it set 'X-Frame-Options' to 'deny' / 'sameorigin' (Browser)Refused to display in…Script error. — Script error. (at line 0) — cross-origin error details hidden (JavaScript)Script error.The canvas has been tainted by cross-origin data — Console: SecurityError: Failed to execute 'toDataURL' / 'getImageData' on 'HTMLCanvasElement': Tainted canvases may not be exported (Browser)The canvas has been t…Failed to…

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