SIM Relay Response – Blocked Script Execution Error After Payment

Jaydeep2026 — Wed, 22 Jul 2026 14:53:25 GMT

I am writing to report a critical issue with our Server Integration Method (SIM) payment flow. The relay response redirect has stopped working, and we are receiving the following browser error after successful payment:

"Blocked script execution in 'https://test.authorize.net/gateway/transact.dll' because the document's frame is sandboxed and the 'allow-scripts' permission is not set."

Our Setup:

Integration Method: SIM (Server Integration Method)

Environment: Test Mode (test.authorize.net) (SANDBOX)

Relay URL: https://2.pmam.com/AgentPortalPaymentAPI/api/payment/callback

Payment Processing: Working correctly – transactions are being approved and our callback API is being invoked successfully

Database Updates: Working correctly – payment status is updated via the relay response

The Issue:

After payment completion, our relay URL returns an HTML response with a JavaScript redirect to our success page:

</body></html>

This redirect was working perfectly before. Now, the browser blocks the script execution due to sandboxing on the transact.dll frame, leaving the user stuck on an empty/blank page. The payment is processed successfully, but the user is never redirected back to our application.

What We Have Already Tried:

Replaced window.location with window.top.location.href – Same error
Used <meta http-equiv='refresh'> redirect – Same error (meta refresh also blocked)
Removed all JavaScript and returned plain HTML with clickable links – Still facing issues with the relay response rendering
Created a new test account with new API Login ID and Transaction Key – Same issue persists
Verified our server response headers via curl – Confirmed that no Content-Security-Policy or sandbox headers are being injected by our server, proxy, or network infrastructure. The sandboxing originates from Authorize.Net's transact.dll frame
Verified the Relay URL is accessible and returning 200 OK – Confirmed working

Our Findings:

It appears that the transact.dll page is now loading the relay response inside a sandboxed iframe without the allow-scripts permission. This prevents any form of client-side redirect (JavaScript or meta refresh) from executing in the browser.

Our Questions:

Has there been a recent change to the SIM relay response behavior or iframe sandboxing policy on transact.dll?

Is there a recommended approach for redirecting the user back to the merchant site within the relay response HTML given the current sandboxing restrictions?

Are the x_receipt_link_url and x_receipt_page fields supported in SIM test mode for post-payment browser redirection?

Is there an alternative parameter or method we should use to redirect the user after payment completion?

Impact:

This is a production-blocking issue. Our customers complete their payment but are unable to return to our application, resulting in a broken checkout experience.

Please assist us urgently. We are available for a call or screen share if needed.

topic SIM Relay Response – Blocked Script Execution Error After Payment in Integration and Testing

SIM Relay Response – Blocked Script Execution Error After Payment