Cannot send or recive mail on yahoo why

If you are using email like OutlookExpress, or Windows Mail, you may have linked to multiple email address' . So when you hit Send / Recive, its checking 2 or more email adds.. If so, one of them is not setup correctly for the Outgoing server. When you create a new email, it uses your default main email address, which is apparently setup correctly. When you reply to a mail which came in on the "other" account the outgoing server setup is wrong, resulting in the message you recieve.
You should go over the server setting for each account other than your default email account.

email address you are sending might be not correct or inactive

One problem is that the incoming (POP) mail server shown in the error message appears to be incorrect. The server address should be "pop.att.yahoo.com" (with a period between "att" and "yahoo"). The incorrect mail server address may interfere with authentication of the sender's email address, which is needed before the outgoing message is sent.

The "530 authentication" message indicates your outgoing (SMTP) server likely requires "server authentication". Also, the "Port 25" message indicates your email program is currently trying to send via Port 25, with no SSL; but Ameritech/Yahoo accounts appears to use Port 465 with SSL enabled.

See more on sever settings for "ameritech.net" users:
http://www.dslreports.com/faq/5535
https://motorola-global-portal.custhelp.com/app/answers/detail/a_id/61941/~/i886---at%26t,-bellsouth,-sbcglobal,-ameritech-email-settings

I would suggest you check the settings for your Ameritech email account in your email program. You may need to correct several settings. The steps to access account settings are somewhat different for various email programs (Outlook, Windows Live Mail, Thunderbird, etc.). You should be able to find guidance in the "help" section of your email program.

Try checking the SSL checkbox for outgoing server.

Looks like their spam filter is stopping your mail.

the message could not be sent because it rejected as the the sender

0x800CCC78 SMTP_REJECTED_SENDER Unknown sender. This is caused by having the incorrect e-mail address in the Reply-To field.

You may have to authenticate in outlook express by putting in the SMTP server name of your internet provider instead of yahoo
for example
Incoming = smtp.mail.yahoo.com
Outgoing = smtp.yourISPservername
Some isp's will not let you send out with a different smtp server than theirs.
It's why you can receive but not send.

Greetings,
this is a server rejected recipient error message for Outlook/ outlook express. mainly if this is a correct email address that you were trying to send the email on then you need to check for the configuration settings for Outlook express.
Goto Outlook express- higlight mail tab- select the user a/c- click properties on right- goto server tab check that server is
incoming: pop3.eastern.com.ph
outgoing: smtp.eastern.com.ph
click save
Regards,
TechSup1

the message could not be sent because it rejected as the sender

u need to enable SSL in your email client