How to fix e-mail client error: Your IMAP server wants to alert you to the following: Please log in via your web browser: https://support.google.com/mail/accounts/answer/78754 (Failure)

1. Go to https://www.google.com/settings/security/lesssecureapps
2. In Access for less secure apps, check Turn on 
3. Go to https://accounts.google.com/b/0/DisplayUnlockCaptcha
4. Click Continue

Source: https://productforums.google.com/forum/#!topic/gmail/oiQxxrovkHs