Hi, as in the subject I am looking for a plugin that will allow players to log on to the 1.12.2 server
How do you mean login? When they join the server they have technically logged into the server? So are you having an issue where players can not join the server? Or do you want a plugin that forces a user to enter a password when they join?
I need a plugin where the player will have to log in immediately after entering the server
He is most likely running a cracked server, so he probably needs a login authentication plugin so people dont steal staff accounts and all that.
Not all password on join plugins are designed with cracking in mind. Some are designed for just that extra bit of security for the server.