what does it have to do with and how do i fix it
when using mirc is says users on 10 and max users 10
if you mean the output from /lusers, then that only depicts the max number of users that have been connected at one single time (only stats!)
if you mean the value from the raw 005, then you have to reconfigure the server to allow more users.
neither way are in the hands of mIRC. mIRC does not control how many users can connect to the server. you should ask the vendor of your IRCd