when connect to ubuntu_16 server,I got an error as flows:

Server does not support diffie-hellman-group1-sha1 for key exchange

solutions: add downloads to config files and restart ssh service

KexAlgorithms diffie-hellman-group1-sha1,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group-exchange-sha256