Internal Server Error messages nginx proxy POP/IMAP/SMTP

[dominus.ceo]

Hi there, 
I have decided delete all authetication part from the email process auth,
and  first made the simplest configuration, so i have configured nginx based
on the the examples provided into wiki nginx page and just modified it to
get an IP address and hostname to redirect my users  to my backends mail
servers, Unfortunadly  I got another   2 error messages :

 upstream timed out (110: Connection timed out) while connecting to
upstream, client: 192.168.122.1, server: 0.0.0.0:143, login:
"ricardo.carrillo", upstream: 192.168.192.78:143


and

client was rejected: "MAIL FROM: <ricardo.carrillo at ine.mx>__" while in auth
state, client: 192.168.122.1, server: 0.0.0.0:25

Does anybody knows what does those errors mean?

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,257206,257230#msg-257230