Your SMTP email username should be same as website email, or at least from same server.

Site E-mail Your website E-mail, it will appear on website's footer and E-mails.

Server Type
Select which E-mail server you want to use, Server Mail function is not recommended.

SMTP Host Your SMTP account host name, can be IP, domain or subdomain.

SMTP Username Your SMTP account username.

SMTP Password Your SMTP account password.

SMTP Port Which port does your SMTP server use? most used 587 for TLS, and 465 for SSL encryption.

SMTP Encryption
Which encryption method does your SMTP server use?