Send mail from C# application not really working?

I have an email application where a user can fill out a form and the info get's mail to the form admin. I have the correct server and email credentials being set and i do not get any errors when the mail is sent. The To and From addresses are the same (admin@thedomain.com) It is like the mail is somewhere in limbo. I know the email account works, because I send mail to it from outlook. Any thoughts?

update: Regarding code, I have 开发者_开发知识库created an abstraction to the System.Net.Mail.SmtpClient class. I can set another server and the code works. The server that does work is within my host’s network. The server that does not work is outside of the network. Strange thing is, like I said, I can setup the account in OutLook and I can send / receive mail fine. I’ll have to check with my vendor to see if the mail is indeed getting to their server.

My guess is permissions. Can your app send an email to your address?

I believe .net's system.web.mail sends email via relay. You need to check with your email admin to determine if your IP address is allowed on the server to relay mail.

It turned out to be a DNS issue with my hosting company. I could send mail via outlook becuase I was direclty connecting to the mail servers. The MX records were screwed up. Thanks to all who looked