Connection failures

Can anyone tell me where I should look to resolve a connection problem reported as below?

[21:32:12] Resolving host name "192.168.0.4"
[21:32:12] Connecting to 192.168.0.4 Port: 21
[21:32:33] A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.
[21:32:33] Client closed the connection.
[21:32:33] Connect failed. Waiting to retry (30s)...
[21:32:33] Active Help: https://www.smartftp.com/support/kb/58

Thanks