Support » Plugin: WooCommerce PayPal Checkout Payment Gateway » Blank modal window with blocked iframe error

  • Resolved 63N


    I’ve been successfully testing orders using PayPal’s sandbox API and PayPal Express Checkout, but I’ve noticed a problem…

    When checking out, normally clicking ‘Checkout with PayPal’ opens a new small browser window, then I log in with the sandbox account, confirm, etc. All works fine and the order goes through.

    But, if the sandbox buyer account is already logged in before checking out, when the checkout button is clicked, a blank modal window appears (not a browser window as before). In the web inspector there’s an endless loop of errors:

    Blocked a frame with origin "http://(development website)" from accessing a frame with origin "". The frame requesting access has a protocol of "http", the frame being accessed has a protocol of "https". Protocols must match.
    pollMiniBrowser - checkout.js:554

    Is this just a quirk of using the sandbox?

Viewing 4 replies - 1 through 4 (of 4 total)
  • Plugin Contributor Hannah S.


    Automattic Happiness Engineer

    I’ve tested this on my own sandbox site and have not been able to reproduce it.

    Issues like this are usually caused by either a conflict with your theme or with another plugin. You can read more about plugin and theme conflicts here:

    The best way to determine if the issue is being caused by a theme and/or plugin is to do the following:

    1. Temporarily switch your theme back to the [WordPress Twenty Sixteen Theme](
    2. Disable all plugins except for WooCommerce
    3. Test to see if the issue has been resolved.

    If that resolves the issue, then slowly re-enable features until you find the one that’s causing the conflict. If it doesn’t resolve the issues, please let us know so that we can help figure out where the problem is coming from.

    I’ll try and go through those checks and report back.

    I’ve noticed the problem is repeatable by clicking the express checkout button on the cart page, logging into a PayPal sandbox buyer account, then instead of continuing with the purchase, click the cancel button. If you immediately click the express checkout button again, the same blank modal window appears with the same iframe error. As mentioned here:

    So, it looks like this problem is already being worked on?

    • This reply was modified 1 year, 10 months ago by  63N.
    Plugin Contributor Hannah S.


    Automattic Happiness Engineer

    You’re completely right – it’s already been logged as an issue here:

    Does that cover your issue?

    Yea, it seems like it’s all related. I’ll keep an eye on it! Thanks

Viewing 4 replies - 1 through 4 (of 4 total)
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