I am unable to send email in piwik

hi guys

I trying to send email manually.But its not working its giving this error

An error occurred while sending ‘HTML Email Report - 8.2017-08-25.1.en.html’ to xxxxxxxxx@gmail.com. Error was ‘5.5.1 Authentication Required. Learn more at 5.5.1 Change SMTP settings to check Gmail on other clients - Gmail Help x124sm10317085pfx.65 - gsmtp’

any body can help to solve this error.


Did you follow this guide exactly?

Have you provided the username and password to the gmail account?
Have you by change enabled two factor authentication or something like this?