On a NW5.1 server running BM3.8 (200 unit license) we have the NW5.1
server+5 license. It is used for firewall, proxy and vpn services

Can we use the DISABLE LOGIN to keep people from making connections to
that server? (And will an admin user sitll be able to connect to it?)

I've never been clear on this and we are getting POLICY
MANAGER - (5.00-015): Unable to obtain a connection license unit.
Operation will continue messages.