I just configured an IMAP account in Windows 8 Mail app.
I can receive but I can't not send email. They get stuck in the outbox.
I'm 100% sure the configuration of the account is fine.
What can I do?
Where is the send/receive button?
okay so as @nerdwaller said, you would need to take a look at your outgoing mail settings. Best is to either change 587 to 465 (as suggested by nerdwaller) or vice versa. The other important thing is the authentication/security of the outgoing server. A generic smtp server would be mail.domainname.x (i.e mail.thisismydomain.com). Normally the authentication would be set on Password. In your case it might be 'None'. The mail server on the ISP's side might also be configured to send only email on TLS security. The best would be to try the different authentication settings and see which one would work. I am not sure which email client you are using, but I can tell you it is normally under options, account settings and at times under advanced settings.
If all else fail, kindly paste the smtp settings (server, port & authentication).