Excluding one specific site within a multisite install. Is it possible?

[MarceloPedra]

Hello guys, I've tried this by unchecking the option to use a single file but the options are greyed out in every site of the multisite. Then I tried entering the domainname.com/* in the textarea to "Never cache the following pages:" but it didn't work either.

Any workaround? Or is this a bug?
I'm using last version with WP 4.9.1

Thanks in advance!