[Discuss] question about imap

[J.Bakshi]

I am running imap server at a remote server. now I can see two imap ports 
there namely 143 and 993. both are working fine but interested to know the 
difference btwn these two.

I have a problem regarding TLS authentication. note TLS encryption is working 
with both the ports. but whenever I enable the TLS authentication it reports 
an error.

with port 143 it reports *TLS/SSL failure for 87.230.8.228: SSL negotiation 
failed
*

with port 993 it reports *Certificate failure for 87.212.8.12: self signed 
certificate: /C=US/ST=NY/L=New York/O=Courier Mail 
Server/OU=Automatically-generated IMAP SSL 
key/CN=localhost/emailAddress=postmaster at example.com

could any one suggest the possible solution and the port (btwn 143 and 993) I 
should use (and why ) ?

thanks