Publishing Pixels – Bad URL. (HTTP/1.0 403 Forbidden or 404 File Not Found)

This error can happen if you are testing the publish.php page (pixel upload) and you have 'Validate URLs' feature turned on in Main Config.

The reason is that you have entered an invalid URL which PHP cannot verify.

Fix:

1. Correct the URL

or

2. Turn off automatic URL validation in Main Config.