unable to create email

I have a similar issue as this guy https://www.youtube.com/watch?v=Hy0caXzTzIA&feature=youtu.be.

While he is able to resolve the issue by disabling cmod security in Cpanel. But my issue still exist. Does anyone know how I would be able to resolve this issue?

I also cannot create emails and disabling mod_security has not helped.

From where do you get the source code or who make the Mautic setup?