I cannot send E-mails

I have just installed eM Client with Windows 7. E-mails are received loud and clear, but when I try to send one, it sits in the Outbox and never reaches the intended recipient. Can anyone suggest a solution?

Are you using Imap or pop settings ?

You need to check your SMTP settings and verify that they are correct.  Check with your email provider for the correct settings.  Do you get an error message?  Screenshot?