After form submission, iredirect to a custom URL

To redirect the form after form submission please take the following steps:

1. Click on "Setup and Embed" tab on the form builder toolbar
2. Click on "Thank You" button on toolbar
3. Select "Custom URL" and click "Next"

4. Enter the url address of the page where the fomr is to be redirected.

i do this,but still can't redirtect to a custom URL,please tell me why，thanks

Please lets know your form's URL or ID and will check to see what would be the issue.