Minecraft Blocking different launchers ?

[BunyaminEfe]

How can I prevent it from coming over different clients when logging into the minecraft server in c# Java can also be done here, but c# can you help?

[BasicallyWiz]

I think your problem is the in-server authentication. Even if you launch Minecraft from different launchers, if you try to join a single server twice with the same account at once, the server will drop or refuse the connection to one of the clients.

There is no fix, buy a second account.