I have installed exim4, but when send an email this error happens:

T=remote_smtp defer (-53): retry time not reached for any host
T=remote_smtp defer (110): Connection timed out
T=remote_smtp defer (101): Network is unreachable

I tried use telnet to test, and this error happens too:

telnet ANY_IP 25
Trying ANY_IP...
telnet: Unable to connect to remote host: Connection timed out

How i can solve this problem?