Sending EMail thru SMTP server in C# - Most of the time not successful?

Question

Hi, In my C# code, i am sending emails thru my local SMTP server. When i ran the code, it was sending emails sometimes and sometimes not. Most of the time, it fails. Even if i don't specify the SMTP server(so that it uses local SMTP server) name/IP, it is still not working most of the time. Any help? Thanks in advance. Regards, Peri