I was playing with my Raspberry PI with Raspbian and the ssh connection was dropping (or timeouting, or something like this), I got a "Broken Pipe" message, and If I tried to connect again, it refuses it.

I don't know why, but to fix it edit /etc/ssh/sshd_config with

sudo nano /etc/ssh/sshd_config

Search for TCPKeepAlive and update it from yes to no

TCPKeepAlive no

It doesn't make sense, I know, but it worked.

Abraços