If you can’t send outgoing mail through your email client, it may have to do with the port you’re using for SMTP. In a lot of cases, port 25 (the default SMTP port) is blocked to prevent spammers because it’s unsecure. To bypass this, you may need to set your SMTP port to 587 in order to send email. At the same time, you may also need to make sure your email client is set to require authentication for your outgoing server (SMTP).