You don't have permission to access on this server

Hi. Since I registered to Cloudflare, I have terrible problem with my wordpress. I can’t update or add new posts as whenever I try I have a message:

You don’t have permission to access on this server.

What can I do about it? Thanks.

You most likely have an IP whitelist system in place. Make sure your server software is restoring visitor IP addresses

Thank you. I believe I should e-mail my hosting provider to find out, am I right?

Yes, some hosting providers might not support CF though and will refuse to help with issues.

Thank you, they helped me.