How can I stop people from accessing the admin page?
Can you add a user and password?
I'm sure your query will rot in this forum because Asternic's support team is too busy enjoying their vacation, many are still working from home in this situation to support their customers, but not Asternic, they just want you to Pay, Pay, Pay and give you buggy applications and lousy support till you get frustrated and switch to "iSymphony".
I've been using FOP2 with Asterisk for years now and I had the same question when I started, but these guys didn't have the answer, so I figured it out myself.
I might have a solution that can help, but I need to know what platform do you use (freepbx, freeswitch, asterisk etc.), the sooner you tell me that, the sooner I can share the solution.