Why cant I connect to outgoing mail server?

In outgoing server settings a WARNING message appears. It reads: cannot connect to the mail server to verify your account information. your server is not responding. how do i fix this?

crwdns2934089:0crwdne2934089:0 crwdns2934093:0crwdne2934093:0

crwdns2934109:0crwdne2934109:0

crwdns2889612:0crwdne2889612:0 0
crwdns2934285:0crwdne2934285:0