Mail Problem

After Submit Tab,
in Send notification email when i edit, there im just add this
(To email address(es) and Email subject) and im sending test mail but it’s not going and it’s showing an error this: (there was an error sending mail, please check the configuration). to resolve this what i have to do?

and i dont have any domain im just checking on my pc.

https://ww.wp.xz.cn/plugins/smart-forms/