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I can receive mail very well but I can't send any? Can any one figure this out?

Speak to your school sysadmin, you probably have the wrong settings.

It won't be a problem with the application itself, provided your school network uses standard POP, IMAP & SMTP protocols.
 
You are probably trying to use your home ISP's SMTP server on your school's domain. It is common practice to block outside SMTP server access. This is a standard security measure intended to reduce SPAM. In some cases, you can get around this by using Port 587 rather than Port 25. If this does not work, then you will have to use your school's SMTP server.
 
You are probably trying to use your home ISP's SMTP server on your school's domain. It is common practice to block outside SMTP server access. This is a standard security measure intended to reduce SPAM. In some cases, you can get around this by using Port 587 rather than Port 25. If this does not work, then you will have to use your school's SMTP server.

How do I achieve that?
 
Your school's IT website probably has either instructions on setting up a mail client or a phone number you can call to ask them what you need to do.

It sounds like you have the incoming mail with the correct settings but the outgoing mail has a problem- maybe a POP vs. IMAP issue or simply the wrong outgoing mail server.
 
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