Reminder, about extra. IP and BrainyCP
In order to apply to the site, in BrainyCP, another IP address, different from the original server one, you must first settle down with this IP address.
Using the example of my situation, I ordered an additional one from the hosting provider itself. And in the control panel of the hosting provider in the list of domains in the A record of the domain, we insert our new IP address.
After that, go to the BrainyCP control panel, go to the Management - IP Address Manager section. There we add our IP address at the very bottom, where there will be a heading "Add a new IP address or route"
After that, our new one should appear on the same page in the list of IP addresses.
After that, we go to our hosting tariffs, edit the current one and, when editing, simply select the second IP address.
After we proceed to editing the host account. By the same principle, we select the second IP address and save it.
After that, it will be possible to bind our added IP address to the edited site.
Added about subdomains.
If the site has subdomains with additional. IP address, you must not forget to select a new IP address in the list of hosting domains in the A record of the subdomain.