Seems like cdosys.dll is not registered on your server.

Please try to register it (regsvr32).

See http://www.dotnet247.com/247reference/msgs/28/141472.aspx or http://support.microsoft.com/default.aspx?scid=kb;en-us;Q171440

Thanks for your reply! Seems like I've made some headway - I now get three error messages in the Gemini log for each attempted send:

Could not access 'CDO.Message' object.

at System.Web.Mail.LateBoundAccessHelper.CallMethod(Object obj, String methodName, Object[] args) at System.Web.Mail.CdoSysHelper.Send(MailMessage message) at System.Web.Mail.SmtpMail.Send(MailMessage message) at CounterSoft.GeminiPlugins.MailPlugin.SendMail(String smtpServer, String fromEmailAddress, String subject, ArrayList emailList, String body, MailFormat format)

>>>>> then:

Exception has been thrown by the target of an invocation.

at System.RuntimeType.InvokeDispMethod(String name, BindingFlags invokeAttr, Object target, Object[] args, Boolean[] byrefModifiers, Int32 culture, String[] namedParameters) at System.RuntimeType.InvokeMember(String name, BindingFlags invokeAttr, Binder binder, Object target, Object[] args, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParameters) at System.Web.Mail.LateBoundAccessHelper.CallMethod(Object obj, String methodName, Object[] args)

Inner Exception

>>>>> then:

The transport failed to connect to the server.

Inner Exception

<<<<<<<<<

Still no evidence that the SMTP server is seeing anything at all. I'll keep looking - any suggestions are certainly appreciated!

- Gary 

P.S. I've tried with different authentication settings in web.config, including no authentication (and made sure each variation was good on the SMTP server). Same results with all.

OK, it seems to be working now. With the above "improvement" noted (extra error messages), I went through the following:

Changed SMTP authentication to "OFF" (which I allowed on the SMTP server), but got the same messages.

Set the <add key="SMTPServer" value="DNS name of mail server" /> rather than an IP or loopback address (Gemini is running on the e-mail server box for now).

After this change, the first two errors appeared unchanged, but I got "The server rejected one or more recipient addresses. The server response was: 550 5.7.1 Relaying to MIKE@MYASD.COMdenied (authentication required) / Inner Exception" as the third message.

As suggested at www.systemwebmail.com (referenced in Gemini manual), I added aspnet user to the local admins group and restarted IIS. This didn't change the result or the error messages.

Set the authentication to NTLM, and did now get a different third message: "The message could not be sent to the SMTP server. The transport error code was 0x80040217. The server response was not available"

So, went and explicitly assigned "Full Control" to the cdosy.dll file for user aspnet. Not sure why this would've been different than being a member of the Admins group, which did have full control on the same file...? But hey, it still didn't work, and the error messages were unchanged.

Last, I changed the SMTP auth = BASIC, and surprise! It worked. Went and removed aspnet from the admins group, restarted IIS, and . . . it still worked.

So, I'm guessing that registering cdosys.dll, and setting explicit full control permissions on it for the aspnet user account (and using BASIC authentication and credentials in my case) were the essential elements to fix the problem. Oh, and using 127.0.0.1 as the SMTP server still does not work - so using the DNS name makes an important difference for some reason in this case.

Thanks for your help, this is closed! - Gary

Gary, thanks for sharing your solution with us.