How to get rid of Server Unexpectedly closed network connection error?

Question

PuTTY

When you enter putty and enter your username and password, if you enter it correctly, the Fatal Error: Server Unexpectedly closed network connection error occurs. The question is how to get rid of this error, I already tried to change in the option connetcion Second between keepalives (0 to turn off) and did 0, and 3600, but all without the original