Problem when sending emails with asp.net

[William]

Hello all,

I'm actually having some troubles when sending mails with a basic asp.net
application, using System.web.mail class.
My test machine is correctly configured, and the SMTPMAIL.SMTPSERVER is set
to the DNS Name of our internal Exchange server.
The problem is in production: if I change the name of the Exchange server by
the one of our customer, I'm having this error message:

Could not access 'CDO.Message' object.

My SMTP server is in the Trust Zone and the web server is in the DMZ, I can
access the SMTP server via Telnet, and everything is working well, the
relaying is correctly configured. I've tried to remove the
SMTPMAIL.SMTPSERVER argument or to change it to localhost, or the IP
address but all failed.

Could somebody help me?

You can send me answers or tips at: magicwil (at) hotmail dot com

Thanks for the help

 

[William]

Re: Problem when sending emails with asp.netChristoph,

I've already visited this website and tried many of its solutions but none
of them helped me. Indeed, it's a very nice website and I recommand it to
many people who need information about mail class using ASP.Net.

I have tried to uninstall dot net framework and reinstall it, even to repair
possible mappings with IIS but none of these solution helped me. I'm going
crazy with this stuff...


William

William,
Have you looked at the System.Web.Mail FAQ at http://www.systemwebmail.com?
It discusses number of scenarios that would cause that error message [0].
HTH,
Christoph Schittko
MVP XML
http://weblogs.asp.net/cschittko
[0] http://www.systemwebmail.com/faq/4.2.3.aspx

 

[Freddy]

I once had this problem. I found out that if you miss out the from email
address(i.e sending a null value to the from email address variable by
mistake) this error comes up. I corrected this and it worked fine for me.

Our SMTPMAIL.SMTPSERVER is mail.xyz.com on development server and localhost
on production server.

Freddy

 

[William]

Thank you for the tips Freddy. I have checked it but all the addresses I use
are correct. We made more tests in our labo, and the problem seems to come
when we separate the DMZ server from the TRUST-Zone server thanks to a
firewall. The mail server is in the Trust zone and the web server in the
DMZ, and we opened all the ports (in our labo of course, not in production
^^) of the firewall but the error persists. It is very strange because if we
put both server in the same range without any firewall then it works. I have
a bad feeling about this, does somebody has already heard strange things
between Netscreen Firewalls and the System.web.mail class?

William

 

[William]

OK I finally found an issue.
I tried to send 2 mails at the same time. Now I totally manage the first
mail, and send it, then I manage the second mail and I send it too, and it
works. A little strange, but if it works, that's all that matters