How to Protect this page with username and password
or
how to protect this page for everyone
set IP addresses which can access this page in here:
But this will be block the whole www services which includes hotspot login too.
You didn’t specify you wanted to run hotspots.
Move the configuration service to port 81 (or something else) and then block that port via firewall:
/ip service set [/ip service find where name=www] port=81