Unable to relay error

[jayy66]

I dont know if im in the right forum because i believe this is a configuration issue.
I have a VB.NET application that sends emails out to a given email address. the application works fine on all company computers except for one which throws the following error:

The server rejected one or more recipient addresses. The server response was: 550 5.7.1 Unable to relay for someone@someEmail.com

The computer is set up like everyone elses and the users account has permissions on the smpt server like everyone else. I did some google searches and found that I had to enable the IIS to relay through the localhost. I tried that and i still get the same error. Does anybody have any suggestions?
If there is another forum for this question, can someone point me in the right direction?

Thanks



"Bugs are good for building character in the user

 

[cjelec]

Does the main smtp server have ip or name blocking?

Is this pc on a different subnet?

Is outlook configured to use the relay? and if so does it work?

Do you have email antivirus on the pc? Is this configured to use the relay?

Or the really stupid question, is the address spelt right, without spaces or incorrect caps...

 

[jayy66]

Im not sure about the first question.
The pc is not on a different subnet, outlook is configured to use the relay and it does work, the anitvirus is also configured to use the relay and the email address is spelled correct.

basically, the user can email anybody from outlook without problems but can not email out of the application. However, I dont think its the code since every computer in the company has the same version of the application and can email from it.
Thanks for your reply.

"Bugs are good for building character in the user

 

[cjelec]

Ok,

The first question was answered by the outlook one.

If you enable loging on the iis smtp settings, what does it say when you try again? I think that the log file will be c:\windows\system32\logfiles...

I have had a simular problem, but gave up and disabled iis smtp and used a main one(proxy) on the network. I had to configure the av, outlook... to use the proxy as well.