# Mail Server Responded: 5.7.1 Relaying not allowed



## jld11145 (Jun 11, 2005)

I have four POP accounts set up on Thunderbird on a laptop and I get the message, noted in the Subject window, when I try to send e-mail. I have set each of the SMTP settings to default in each of the accounts and get the same message. This morning I was able to send and receive e-mail from home; at my office this afternoon, I was able to receive, but not send messages. Using the same account settings in Outlook, my messages went out flawlessly. I would appreciate any help I can get with this problem.

Joe


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## brendandonhu (Jul 8, 2002)

Is the SMTP server your ISP's for the home computer? They might only accept mail coming from their own connections, hence it not working in your office.


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## blin (Aug 3, 2003)

quoted from http://www.chicagotech.net/E-mail.htm

550 5.7.1 relaying denied - ip name lookup failed

Symptoms: when sending a mail to [email protected], you may receive undeliverable message like this:
<mail.chicagotech.net> #5.7.1 smtp;550 5.7.1 <[email protected]>... Relaying denied. IP name lookup failed (x.x.x.x).

Possible Causes:
1. DNS lookup failed
2. The sender of the message does not have the privileges required to complete delivery.
3. You are trying to relay your mail through another SMTP server and it does not permit you to relay.
4. The recipient might have mailbox delivery restrictions enabled. 
5. Make sure you mail server is no on a spam list.
6. If there are a lot errors and warning such as ID 104, 215 related to spam and virus in the Application Event Viewer 
of the Exchange server, you may need to restart the Exchange services.


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