Insert Headers and Footers wordpress plugin leads me to 403 error page

Question

I have a WordPress website and I just want to connect come API and return some data the problem is that I can't add any script insert headers and footers plugin, cuz every single time I try to add a script I press save I get the 403 error page even simple scripts like

<style>
   *{box-sizing:border-box;}
</style>

is not working and still showing the 403 error page

Answer 1

this usually cause by a security/firewall plugin or security settings from your server. Firstly, temporary disable any security/firewall plugin on your site, save your changes and reactive the plugin later.

If you don't have any security/firewall plugin installed, then temporary remove any security/firewall settings on your sever, save your changes and reactive later.