There was a similar issue in some of the previous versions of the RadCaptcha, which occurs when both the refresh image and the captcha audio features are enabled, as you can see in this forum thread
. The discussed problem has been fixed and does not exist in the latest official release. Please try upgrading your version of RadControls for ASP.NET AJAX to the latest release and check if the issue persists.
Note that at the current state of affairs I am mostly guessing as to what your setup is. If you are still experiencing difficulties please open a support ticket
and send a sample, runnable project that displays your issue
so that we can examine it locally and provide a more to the point answer.
All the best,
the Telerik team
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