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.

Hi,

Did you follow this guide exactly?
https://piwik.org/faq/how-to/faq_93/

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