question :(

[Jacobob14]

recently entered one player in to my server

with account Console

and gave ban all staff

as it did to enter the Account Console

and how I can prevent it from happening again?

[myonlake]

You must set the ACL permissions denied for those commands on the group "Default".

[Hell-Mate]

   "command.ban" access="false">
        "command.banip" access="false">
        "command.unbanip" access="false">
        "command.reloadbans" access="false">

[Jacobob14]

my problem is how he has to connect to the console

[Hell-Mate]

my problem is how he has to connect to the console

well open ACL.XML and add this line under console group.

"Console"> 
        "Moderator">
        "SuperModerator">
        "Admin">
        "RPC">
        "user.Console"> 
       -- this line -->  

or simply add yourself to console group from admin panel and remove acc names of these ppl who banned all staffs.

[Mr_Moose]

There is a few ways to access the console from outside thought, I guess most of the servers has the web admin interface up and running, usually on port 22005 with the same public ip as your server, if this player entered that page and logged in with any admin account or similar he could ban all of you "from the console" so maybe it's someone that know your password or has a admin account in your server.

As many other replied above, you should check the acl file and make sure that the rights are correctly setup, but as an addition to that, never add people you don't know to the staff team. MTA is full of scammers which has smaller servers as their targets, they simply join your server and ask if they can become admin, if you say no they will try to offer you scripts, maps and other stuff (mostly stolen or just downloaded from the community). As soon they get the rights they simply ban you and steal your recourses or does other harmful things just to destroy for you.