Not sure when it happened, but must have been recent as I have been adjusting the settings in the last few weeks, but the block auth by country section (domain / general) is greyed out saying that the settings are controlled by your system admin. I am sysadmin, I am logged on as such. 

Is this a bug that has recently appeared? I have noticed that I can now only add my own country, not others

It's happening on two servers that I manage

Linux 9546

IGNORE - newbie error, I found the place to edit over in settings / general. Heck, I've just manually reattached 93 mailboxes, i'm tired!!