Gmail-acess for less secure apss

If gmail ID ,password ,incoming pop servers ,outgoing smtp server and all other settings are correct but Outlook  or other e-mail client continuously prompting for credentials then it may be the problem in gmail "less secure apps" setting.Just go below link and turn off "access for less secure apss " option.Then try again.

https://www.google.com/settings/security/lesssecureapps

Some apps and devices use less secure sign-in technology, which makes your account more vulnerable. You can turn off access for these apps, which we recommend,