Gmail stops

Hi,

I followed http://postieplugin.com/getting-started/ but Gmail stops Postie to access.

Google translated message from Swedish:

Logon attempt thwarted
Hi!
Anyone attempting to log in to your Google account xxx@gmail.com just an app that does not meet modern safety standards. Detailed information:
Monday, February 8, 2016 08:14 (Central European Standard Time)
Denmark*
We recommend that you use a secure app to access the account, such as Gmail. All apps that Google has developed meet these safety standards. However, if you are using an app that is not as confident it can happen that your account will be vulnerable. Read more.
Google prevented this login attempt, but you should look at devices that have recently been used.

What to do?

https://wordpress.org/plugins/postie/