https://blog.it-kb.ru/2015/10/06/apc-ups-network-management-card-nmc-ssh-connection-from-putty-error-disconnected-received-ssh2_msg_channel_success-for-nonexisting-channel-65536/
APC UPS Network Management Card (NMC) - Проблема подключения из PuTTY по протоколу SSH2 - Disconnected Received SSH2_MSG_CHANNEL_SUCCESS for nonexisting channel 65536