Whitelist my IP

Go here — https://waf.sucuri.net/?settings&panel=access-control

Then you cannot whitelist your IP address.

That website that you linked in your original post is being protected by the Sucuri Firewall, one of our customers created an account and added the website there, and one can only do that if the person also has administrative access to the website. If you don’t have access to the Sucuri Firewall then you have to ask the person who has control over the account to whitelist your IP.

EDIT: Taking a quick look at the screenshot [1] that you provided, it seems that you are trying to use a backdoor to delete some content from the website, that’s why the Sucuri Firewall blocked your IP address.

[1] https://image.prntscr.com/image/l1UK22bKSqupz-SzHlLw5g.png