Yes , I am also facing the issue and I know one reason why it is.
actually Google offered advanced security protection to their e-mail to stop hackers to attack their users. They have placed a new security service and nothing but 2-step verification.
So every time I have login from Ubuntu I will get a red warning at system options where we have online accounts menu. Again I need to click that and then I need to authorize it.
It will provide me a message windows like this & I need to enter the password everytime which will be received by my mobile everytime.
If I want to remove this , I can do that :). Google also providing an Unique password for applications. If your google account have to get logined from the application then , If you enter your login password that will grant the temp access through the application. If you have entered the application password that was created at the google then you no need to enter the login password everytime and no longer grant access process .
https://support.google.com/accounts/answer/185833?hl=en