Problem with idSMTP

[topcat01]

Hi All,

I am using idSMTP to send my users emails, for the most part this has been working well however sending an email to one email address in particular always fails and I get the error:

'550 Mailbox unavailable or access denied'

The example problem email address is 'example@comcast.com'

I can hapily send and receive messages to this user via Outlook express so don't see what the problem is. I have been told it has to do with authentication however I have this enabled. I can't see what difference exists between my program (which works 99% of the time) and Outlook Express.

This is the code I am using:

try
try
idSMTP1.Connect(1000);
idsmtp1.Authenticate;
idSMTP1.Send(idMessage1);
except on E:Exception do
MemoStatus.Lines.Insert(0, 'ERROR: ' + E.Message);
end;
finally
if idSMTP1.Connected then
idSMTP1.Disconnect;
end;

TIA

 

[Griffyn]

SMTP 550 is a relay-denied error. The responding mail server can provide any text it likes for the error, but the 550 bit indicates that it is refusing because of a configuration issue.

Questions:

- What SMTP server are you sending to? Is it the same server you've configured in your Outlook Express setup?

- If the servers are the same, are you connecting from the same machine? If not, then the SMTP server may be rejecting you because of the IP address of the sending machine, or the subnet you are on.

- Try not authenticating for this e-mail address. In your code you would implement this by catching and checking for the 550 error in a try..except block, and then retrying by connecting without authenticating.

 

[topcat01]

Hi Griffyn,

I've checked the OE settings against the settings in my delphi app - everythimg matches.

Both the tool I am developing and OE are installed on the same computer, I use one machine for everything.

My original program did not have authentication and I had the same problem. I only recently added authentication but that hasn't helped.

I'm stumpted!

 

[Griffyn]

Some more things to try:

- Ensure the From.Address property of the message contains an e-mail address of the same domain you are sending from in OE. This is not the same as the Sender property of the message.

- If you can, try contacting the administrator of the problem recipient's mail server to see if they have any clues as to why you're being rejected. Perhaps they have a spam filter turned on. If so, they should be able to tell you what properties of your message are setting it off.

- Ensure you have the From.Name filled in.

 

[topcat01]

Griffyn,

Thanks for all the helpful comments, I tried all you suggested and then some. I am putting the error down to the way comcast is handling the message. I have not had a problem with any other email provider so it must be something their end.

Thanks again