About ybb account....

I'm not able to send mail to my friend who has ybb e-mail account. Is there any problem about the ybb in Japan? How can I contact my friend again? I don't have any address other than this e-mail, which I'm not able to send or receive any mails. pls help.

It sounds like to me that your friend either changed his/her address without notice, or stop using ybb for some reason (switched to another internet provide, for example).

Thanks for your suggestion. I try to send mails but they are returned back saying 554 error. Do you have any idea what it is about? Thanks again.

554 is the generic 'transaction failed' errors. It doesn't necessarily mean that the mailbox is gone or full, but it could mean that your originating domain is refused because it got blacklist, or so. Try again in a couple of days time, would be my suggestion.

Thanks Kappa. What do you mean by Black list. I'm confused! Can you tell me about it. I'm coming across these things for the first time. I'm very genieun person.

Some domains and or IP addresses get blocked by the destination Internet service providers (ISPs) if they are known to have sent a lot of spam messages; this might apply to your PC if it has been infected by some spyware. See http://www.spamhaus.org/sbl/ for more about blacklists.
It is a bit of old technology as nowadays the contents get scanned for certain keywords and then refused on an email by email basis which makes more sense, but caused the spammers to deliberately misspell words. Anyway, the 554 error code usually shows up when an email is refused for some reason which wasn't in the original email architecture document. However, if your IP address is blacklisted, it usually means that you will also have problems sending email to other addresses. Therefore, it is very well possible that the ybb server is just reporting a simple thing like a full email box in an awkward, not standard way, or so.

Things you can try: Run a reliable spyware program (PC Tools Spyware Doctor, for instance) or try sending email from a different internet connection or create a gmail address, or so.

Thanks Kappa for explaining me about the Blacklist. I can send and receive mails from my other friends and siblings from this particular email. I have no problem with my other email accounts too. I also tried your suggestion from sending mail from Gmail account. Another thing, I tried to send mail from yahoo account, Gmail, Hot mail. I get the same error. My friend just knows my Yahoo email address only. So what do you think about this now? He is one of my best email pal. I tried enough to get in contact from various emails to tell him the problem.

I also tried your suggestion from sending mail from Gmail account. Another thing, I tried to send mail from yahoo account, Gmail, Hot mail. I get the same error.

Did you fail even from web mail interface?

When you got 554 Error message, isn't it accompanied by any additional info?
Here's the examples:
http://help.yahoo.co.jp/help/jp/mail/in_trouble/in_trouble-2...
(554 Error messages returned by Yahoo!Mail (Japan), Japanese language shown on the page is mainly translation of the original error messages in English.)

Remote host said: 554 delivery error: dd This user doesn't have a ybb.ne.jp account

Please tell me how to try from web mail interface? What is it? Did you succeed to get in contact with your friend from the web mail interface?

Yahoo!Mail
http://mail.yahoo.com
Gmail
http://gmail.com
Hotmail
http://www.hotmail.com

You can send/receive email with your web browser, not using your email reader.

This user doesn't have a ybb.ne.jp account

What if you send email to yourfriend@yahoo.co.jp, not @ybb.ne.jp?

@yahoo.co.jp is a free email account (like @yahoo.com) but Yahoo! BB ADSL users have @ybb.ne.jp as well and these addresses share the same mailbox.

If your friend was using Yahoo! BB ADSL and has cancelled it, @ybb.ne.jp is no longer available, but @yahoo.co.jp should be still available.

I tried all your suggestions. but did not get in contact with my friend.Thanks for all your suggestions.