I can receive mail but not send why?

• The most common is that you have not enabled secure authentication (SSL).

Do this:

1. Go to your email program.
2. Settings > Account.
3. Make sure to check "Secure connection", "Secure authorization", "SSL" or something securi.
4. Note that the incoming mail server may not require authorization. If you stop getting mail, uncheck secure authorization on incoming mail server.