Outlookexpree SMTP problems.

Here are the settings for that: https://help.yahoo.com/kb/SLN4724.html

Good luck

If you are receiving an error when sending email using Outlook:

"The message could not be sent because one of the recipients was rejected by the server. Server Response: '550 not local host, not a gateway', Port: 25, Secure (SSL): No, Server Error: 550, Error Number: 0x800CCC79"

Open your Outlook settings (Tools > Accounts)
Go to View/Change email account for the email account you are having problems with.
Check that the SMTP Server is set to yourdomain.com
Go into the "More settings", "Outgoing Server" tab and make sure that the option "My server requires authentication" for the Outgoing server is checked ON.

Save and close all windows.

Try again.

If the problem continues then the problem is that your Internet Service Provider is blocking the mail server. ISPs do this to prevent spam on their network. When this happens you will need to use the mail server that they provide you instead of your own. The mail server is generally smtp.yourISPname.com, however, it could be different so please contact your ISP to get the details.
If you do not want to use your ISPs server for SMTP, and the ISP is blocking port 25, you can switch the port to 587 for your outgoing mail and use mail.yourdomain,com for the SMTP server name.

1. Change the settings in your email software so that the email account you're using designates an Outgoing Email Service that your internet service provider won't block. Your internet service provider should provide you with the address of an acceptable Outgoing SMTP Mail Server. This information is often listed on their website; if it isn't, call their technical support and ask them the address of their Outgoing Email Server. Then go into your email software and change your current Outgoing SMTP Address to the one your ISP requires.
2. After you designate a SMTP address not restricted by your ISP, you may still receive the following error:
Port: 25, Secure(SSL): No, Server Error: 530, Error Number: 0x800CCC78
Now you are reaching the Outgoing SMTP Mail Server, but it won't process your request without further authorization. You will need to go into your Email Software and find the setting that indicates that your Outgoing SMTP requires further authorization. Select this setting and enter the username and password required by your ISP (or reqired by who ever is the administrator of the Outgoing SMTP Mail Server that's not blocked by your ISP). For example, at the time this article was written MSN Internet Service's SMTP Address was: (secure.smtp.email.msn.com). However, this email server won't allow you to use it unless you send your MSN username and password along with your request to send email.

Microsoft Outlook 2002 (XP) and 2003 From the Tools menu, choose E-mail Accounts. Click in the circle beside "View or change existing e-mail accounts." Click Next. Click the email account you wish to modify and then click Change. Click More Settings. From the tabs along the top, click "Outgoing Server." Check "My outgoing server requires authentication”. Also, make sure to check "Use same settings as my incoming mail server." Click OK. Click Next. Click Finish.
Microsoft Outlook Express From the Tools menu, choose Accounts. Select the "Mail" tab. Click the email account you wish to modify and then click Properties Select the "Servers" tab. Check the box next to "My Server Requires Authentication." Click the Settings button. Ensure that Use same settings as my incoming mail server is selected and click OK. Click Apply on the properties dialog box to confirm your changes and to close the window. Click Close on the Internet Account dialog box to complete the settings change. Click Close.

The problem is clearly indicated on the error code.

"the server responded 521 user is over the limit for messages to be sent in a single day."

Have you been sending a lot of messages using that account? From yahoo:

The limit for messages for yahoo is 100 per hour, max 500 per day.

If you believe that you are the one not doing this, you can either report this to yahoo or checked your Yahoo! account immediately. Change the security settings and most specially the passwords. It could be that your account is used as a spam bot.

After deleting and recreating an account in Mail, you might not be able to send emails even if you can receive them. When you try to send a message, this alert may appear:
"Cannot send message using the server smtp.xxxxx.com"
This happens if the Simple Mail Transport Protocol (SMTP) server, used for outgoing messages, was incorrectly entered with the first account even if it was correctly entered for the replacement account.
Products Affected Mail
Resolution You should first verify that the network connection you're using is the correct one for the ISP that you want mail to communicate with.

1. Open Mail.
   
2. From the Mail menu, choose Preferences
   
3. Click Accounts.
   
4. On the Outgoing Mail Server (SMTP) pop-up menu, choose Edit Server List.
   
5. Delete all entries for the SMTP server that is mentioned in the error, and click Done.
   
6. Configure the current SMTP server by clicking Server Setting.
   
   Note: If you need to use multiple SMTP servers for multiple Mail accounts, see this document.
   
7. Send a test message to your email address.

Make sure your SMTP (outgoing) server is set properly.
Are you on your own connection - or using a retail WiFi one?

Normally most WiFi servers reject outgoing mail.
You can GET mail - just not send any.
SMTP is blocked.
Pop3 (incoming) is allowed.

To check that the SMTP is set properly -

Open O/E, and navigate to the following screen....

Tools > Accounts > (Highlight the eMail account you are trying to send from).

Then click Properties

Click SERVERS tab.

It should say...
Outgoing Mail (SMTP): __________________________

In the blank it should say something like: SMTP.ntworld.com
(check with your service provider for the correct SMTP setting)

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Thank You!! :D

Tried to take backup of messages was not able to copy the dbx files
- Rename folders.dbx
- Was able to send/receive messages without any error
May not able to retreive some messages in sent items, deleted items folder

>lets create new identiy
http://support.microsoft.com/kb/209169

most isp blocks port 25 for sending out mail that's the reason you cant send out mail, ask you wifi(ISP) smtp settings and you need to set it on your smtp server so you can send out mail using thier smtp as outgoing server.

OR ask you email provider about your webmail address and manually send out mail using the web interface of your email hosting.

btw have you try to change you smtp port to 587 sometimes it work.

Either the message you are trying to send is too big, e.g contains a too large attachment, or your mailbox on the server is full...