Additional Info.

All e-mails send to yahoo from my server smtp goes to SPAM folder, I just checked header and it seems smtp auhtorization went ok.

<skip>
Received: from 64.191.50.*  (EHLO smtp.myactualdomain.com) (64.191.50.*)
  by mta111.mail.re1.yahoo.com with SMTP; Tue, 22 Apr 2008 09:40:44 -0700
Received: from cl245 ([64.191.50.*]) by smtp.myactualdomain.com with Microsoft SMTPSVC(6.0.3790.3959);
<skip>

I replaced last IP number with *, cl245 is my server name

I am not networking expert but maybe there is some kind of SMTP certificate system where I could buy and install one on my smtp server to prevent spam bots from deleting e-mails send from my server?

www.mxtoolbox.com show report below, as you see MX are ponted to gmail, I am hosting email at gmail.

ns44.domaincontrol.com reports the following MX records:
 
Preference Host Name IP Address TTL    
10 aspmx.l.google.com 74.125.47.27 604800  
20 alt1.aspmx.l.google.com 66.249.83.114 604800  
30 alt2.aspmx.l.google.com 66.249.93.114 604800  
40 aspmx2.googlemail.com 209.85.135.27 604800  
50 aspmx3.googlemail.com 64.233.167.27 604800  
 
4/22/2008 2:21:02 PM Central Standard Time

DNS Host: Unknown
Email Host: Unknown
 
SMTP diagnostic I get

RESULT: smtp.freepdfconvert.com
Banner: smtp.freepdfconvert.com Microsoft ESMTP MAIL Service, Version: 6.0.3790.3959 ready at Wed, 23 Apr 2008 03:30:46 -0700 [47 ms]  
Connect Time: 0.141 seconds - Good
Transaction Time: 0.469 seconds - Good
Relay Check: OK - This server is not an open relay.
Rev DNS Check: OK - 64.191.50.10 resolves to 64-191-50-10.hostnoc.net
GeoCode Info: Geocoding server is unavailable
Session Transcript: HELO mxtoolbox.com - DIAGNOSTIC TEST - See http://www.mxtoolbox.com/Policy.aspx 
501 5.5.4 Invalid Address [78 ms]
HELO mxtoolbox.com
250 smtp.freepdfconvert.com Hello [64.20.227.131] [47 ms]
MAIL FROM: <test@mxtoolbox.com>
250 2.1.0 test@mxtoolbox.com....Sender OK [62 ms]
RCPT TO: <test@mxtoolbox.com>
550 5.7.1 Unable to relay for test@mxtoolbox.com [47 ms]
QUIT
221 2.0.0 smtp.freepdfconvert.com Service  
 
What other info should I send?

There are some things I see but maybe lookinto it some more with this link:

http://www.eventid.net/display.asp?eventid=4006&eventno=4317&source=smtpsvc&phase=1

Let me know what your findings are.

Richard

Thank you for your help!
What I found is that neither of these solutions help me.

I don't use any antivirus, my windows server 2003

Default firewall allow connections on 25 port I can send some e-mails.

My server IP address is entered in IIS6 SMTP relay configuration to allow send e-mails only from server.

I am not sure what I have understood "Greylisting" correctlly, I configured  my IIS6 SMTP server so that it tries to delivery several times with time delay if e-mail fails first time.

I can't access other "M292278, M827601, M919091" link because web page ask for payment.

Also I don't use bare linefeed characters(I refer to http://www.dylanbeattie.net/docs/iis6_bare_linefeed.html) in e-mail body, e-mails is created not from script but from our windows exe program which is hosted on our server and it create fully qualified e-mails.

Will this help? The error you get is
>> 501 5.5.4 Invalid Address [78 ms]
http://support.microsoft.com/kb/291828

Could it be a problem with the script? A space to many?
https://www.experts-exchange.com/questions/23081077/Properly-configure-IIS-SMTP.html

and also error:
>> 550 5.7.1 Unable to relay for test@mxtoolbox.com [47 ms]
Will this help?

Tough nut to crack!

<<and also error:
>> 550 5.7.1 Unable to relay for test@mxtoolbox.com [47 ms] >>

I have disabled relay for all IP addresses except my server, as I understand I should allow relay IP addresses which I trust and want to allow send e-mails. Right?

<<Could it be a problem with the script? A space to many?
https://www.experts-exchange.com/questions/23081077/Properly-configure-IIS-SMTP.html>>

I think, no. Somethign wrong wirh SMTP server.

Can you try to use SMTPdiag?
http://www.microsoft.com/windowsserver2003/iis/diagnostictools/default.mspx

Hope this will point us in the right direction.

Richard

The log is below, I got two error, I don't know what they exactly mean and is this related with my SMTP server problems. Maybe you could explain?

C:\Documents and Settings\Administrator>"C:\Program Files\IIS Resources\SMTPDiag
\SMTPDiag.exe" "jobdone@freepdfconvert.com" "tomas@baltsoft.com"

Searching for Exchange external DNS settings.
Computer name is CL-245.
Failed to connect to the domain controller. Error: 8007054b

Checking SOA for baltsoft.com.
Checking external DNS servers.
Checking internal DNS servers.
DNS server [4.2.2.2] did not return a valid SOA record.
SOA serial number match: Failed with one or more failures.

Checking local domain records.
Checking MX records using TCP: freepdfconvert.com.
Checking MX records using UDP: freepdfconvert.com.
Both TCP and UDP queries succeeded. Local DNS test passed.

Checking remote domain records.
Checking MX records using TCP: baltsoft.com.
Checking MX records using UDP: baltsoft.com.
Both TCP and UDP queries succeeded. Remote DNS test passed.

Checking MX servers listed for tomas@baltsoft.com.
Connecting to aspmx.l.google.com [66.249.83.114] on port 25.
Successfully connected to aspmx.l.google.com.
Connecting to aspmx.l.google.com [66.249.83.27] on port 25.
Successfully connected to aspmx.l.google.com.
Connecting to alt1.aspmx.l.google.com [209.85.135.27] on port 25.
Successfully connected to alt1.aspmx.l.google.com.
Connecting to alt1.aspmx.l.google.com [209.85.135.114] on port 25.
Successfully connected to alt1.aspmx.l.google.com.
Connecting to alt2.aspmx.l.google.com [209.85.199.27] on port 25.
Successfully connected to alt2.aspmx.l.google.com.
Connecting to alt2.aspmx.l.google.com [209.85.199.114] on port 25.
Successfully connected to alt2.aspmx.l.google.com.
Connecting to aspmx2.googlemail.com [209.85.135.27] on port 25.
Successfully connected to aspmx2.googlemail.com.
Connecting to aspmx3.googlemail.com [64.233.167.27] on port 25.
Successfully connected to aspmx3.googlemail.com.

I have tried to execute test send to yahoo mail and gow different result

C:\Documents and Settings\Administrator>"C:\Program Files\IIS Resources\SMTPDiag
\SMTPDiag.exe" "jobdone@freepdfconvert.com" "tomazaz123@yahoo.com"

Searching for Exchange external DNS settings.
Computer name is CL-245.
Failed to connect to the domain controller. Error: 8007054b

Checking SOA for yahoo.com.
Checking external DNS servers.
Checking internal DNS servers.
SOA serial number match: Passed.

Checking local domain records.
Checking MX records using TCP: freepdfconvert.com.
Checking MX records using UDP: freepdfconvert.com.
Both TCP and UDP queries succeeded. Local DNS test passed.

Checking remote domain records.
Checking MX records using TCP: yahoo.com.
Checking MX records using UDP: yahoo.com.
Both TCP and UDP queries succeeded. Remote DNS test passed.

Checking MX servers listed for tomazaz123@yahoo.com.
Connecting to c.mx.mail.yahoo.com [216.39.53.3] on port 25.
Error: Expected "220". Server is not accepting connections.
Failed to submit mail to c.mx.mail.yahoo.com.
Connecting to g.mx.mail.yahoo.com [206.190.53.191] on port 25.
Error: Expected "220". Server is not accepting connections.
Failed to submit mail to g.mx.mail.yahoo.com.
Connecting to f.mx.mail.yahoo.com [68.142.202.247] on port 25.
Error: Expected "220". Server is not accepting connections.
Failed to submit mail to f.mx.mail.yahoo.com.
Connecting to d.mx.mail.yahoo.com [66.196.82.7] on port 25.
Error: Expected "220". Server is not accepting connections.
Failed to submit mail to d.mx.mail.yahoo.com.
Connecting to c.mx.mail.yahoo.com [216.39.53.2] on port 25.
Error: Expected "220". Server is not accepting connections.
Failed to submit mail to c.mx.mail.yahoo.com.
Connecting to b.mx.mail.yahoo.com [66.196.97.250] on port 25.
Error: Expected "220". Server is not accepting connections.
Failed to submit mail to b.mx.mail.yahoo.com.
Connecting to a.mx.mail.yahoo.com [209.191.118.103] on port 25.
Error: Expected "220". Server is not accepting connections.
Failed to submit mail to a.mx.mail.yahoo.com.
Connecting to g.mx.mail.yahoo.com [209.191.88.239] on port 25.
Error: Expected "220". Server is not accepting connections.
Failed to submit mail to g.mx.mail.yahoo.com.
Connecting to f.mx.mail.yahoo.com [209.191.88.247] on port 25.
Error: Expected "220". Server is not accepting connections.
Failed to submit mail to f.mx.mail.yahoo.com.
Connecting to e.mx.mail.yahoo.com [216.39.53.1] on port 25.
Error: Expected "220". Server is not accepting connections.
Failed to submit mail to e.mx.mail.yahoo.com.

>> Error: Expected "220". Server is not accepting connections.
I think this is due to your reverse DNS problem. Let's wait 24 hours to see if this clears up when DNS has updated over on the Internet.

>>DNS server [4.2.2.2] did not return a valid SOA record.
>>SOA serial number match: Failed with one or more failures
I think that's a problem on the side of baltsoft.com. Check the SOA record on www.intodns for this domain!!

>>Failed to connect to the domain controller. Error: 8007054b
Error of no importance.

It comes to the bottom line that your reverse DNS could be the cause of these problems.

Richard

Found a good link on the net also:

http://msmvps.com/blogs/bernard/archive/2004/09/28/14480.aspx

Richard

And this one?
http://www.msexchange.org/tutorials/SMTPDIAGdiagnose-Exchange-2003-SMTP-DNS.html

Richard

I just added SPF record into DNS and these errors almost gone. Thank you for your help.

Thanks for the points. Great it worked out for you

>>these errors almost gone
can I help you with this?

Richard.