blocked by firewall for XSS

Hello, I have bought and installed a plugin that allows me to add banner advertising on my website. When I went to add a new entry, the wordfence prompt appeared to add it to white list. I accepted. But now when I go to add it always gives me a error. I’ve seen Live Traffic do this:

blocked by firewall for XSS: Cross Site Scripting in POST body: postbody=%3Cscript%20async%20src%3D%22%2F%2Fpagead2.googlesyndication.com%2Fpagead%2Fjs%2Fadsbygoogle.js%22%3…

Apparently he’s blocked my ip for that kind of action. I have restarted router to have new ip, deactivated wordfence but still giving error when adding.

I don’t know how to do that allows me to use the plugin I bought.

REgards