returned email with 550 5.1.2 error

Whenever I send email to my dad's office (only my dad's office, this doesn't happen for any other address i send mail to) my email gets bounced back with:

   ----- The following addresses had permanent fatal errors -----
<dadsname@company.net>

   ----- Transcript of session follows -----
550 5.1.2 <dadsname@company.net>... Host unknown (Name server: companysmtp. company.net.: host not found)

This happens when I use two different POP3 email accounts with Outlook Express, AND when I use a Yahoo! account with my name.  However, it does not happen when I use a Yahoo account with a different name.  So, did my dad's office's antispam software suddenly start identifying my name as a spammer, and then refuse to deliver my email?

I've read that it could be becuase my ISP is associated with a spammer, but that's impossible becuase my ISP is provided by my university.

The ONLY reason I may suddenly by identified as a spammer is I wanted to see how "bouncing" worked, so I "bounced" a spam back to the sender of the spam.......would that somehow make my email account look like a spammer too?

How can I fix this?
kathenaAsked:
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

x
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

CrazyOneCommented:
Scroll down to
What do these bounce messages mean?
http://www.shamash.org/help/bouncemsgs.shtml
0
CrazyOneCommented:
http://mail.bcpl.lib.md.us/help/misc/mailerrors.html
Host Unknown
   ----- The following addresses had permanent fatal errors -----
<JDOE@SWITCHGRASS.NET>

   ----- Transcript of session follows -----
550 5.1.2 <JDOE@SWITCHGRASS.NET>... Host unknown (Name server:
mail.switchgrass.net.: host not found)

This means that our mail server was not able to locate the mail server for switchgrass.net (mail.switchgrass.net) in the Internet's domain name service (DNS). If the target system can't be found in the DNS, then our mail server can't connect to the remote mail server to deliver your message.

Most "host unknown" errors are caused by a typo in the domain name part of the intended recipient's address, but an increasing number of "host unknown" errors are the result of trying to reply to junk mail (spam). This is because the "From:" address on junk mail is almost always bogus. Where the address is typed correctly and is a real one, the problem is usually a temporary failure in DNS.

What you should do:
Confirm the intended recipient's address, if possible. Resend your message to the corrected address.
0

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
kathenaAuthor Commented:
Unfortunately it is not that simple.  

There is no way the address is wrong, my dad will send me an email and i'll try to reply to it and it is rejected.

He can receive mail from other people, so his settings are not wrong, and I can send mail to other people so my settings are not wrong either.
0
Introduction to Web Design

Develop a strong foundation and understanding of web design by learning HTML, CSS, and additional tools to help you develop your own website.

RIMSGROUPCommented:
I am suffering a similar, if not the same, situation. I can send to but cannot receive from a single address. The sendor has a second address that works fine. We cannot locate the difference in settings for the two of them.
0
rwarrCommented:
I am having the same problem. I am sending an email from an account on the same domain as the recipient, and it bounces back with the error. An NSLOOKUP for the domain, resolves to the proper address, so I assume the DNS is working properly. I've tried sending to other recipients (different domains) that are on the same server (same IP) and they are delivered fine. It appears that I only receive the error when the recipient's address is on the same domain.
0
RIMSGROUPCommented:
Down to senders machine! It initially appeared I could not receive email from a specific sender. I mistakenly assumed I could not receive from the domain of "canada.com". Since my earlier comment I have picked up 2 clients, both from the domain "canada.com". Both of those are flawless. We missed something when reviewing the senders configuration.
0
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Email Clients

From novice to tech pro — start learning today.