If after connecting the mailbox gmail is not picked up/not sent mail, you need to:

1. disable two-factor authentication - https://support.google.com/accounts/answer/1064203?hl=ru=en
2. Go to the link and press the button https://accounts.google.com/b/0/DisplayUnlockCaptcha, wait 10-15 minutes without closing the tab. After that check the incoming mail: Management - Incoming mail settings - Inboxes - Check your mail.
3. In addition, enable access to unapproved applications - http://www.google.com/settings/security/lesssecureapps
4. Enable IMAP access
Open Gmail on your computer.
In the upper right corner, click the Settings icon.
Click Settings.
Click the Forwarding and POP/IMAP tab.
In the IMAP access section, select Enable IMAP.
Click Save changes.

Information link: https://support.google.com/mail/answer/7126229?hl=ru=en