Turn off 2-Step Verification

Did your email client or applications stop working when you turned on 2-Step Verification? Don't fret -- you can get applications and devices that need access to your Google Account working again in minutes using application-specific passwords.

Turning off 2-Step Verification

Visit the Using 2-Step Verification page under your Google Account settings. Sign in with your username, password, and verification code if prompted.
Click Turn off 2-Step Verification.
A pop-up window will appear to confirm that you want to turn off 2-Step Verification. Click OK.

Revoking and destroying passwords and codes to protect your account

If you used application-specific passwords to authorize applications to access your Google Account, we recommend you go back to using passwords -- rather than application-specific passwords -- to access these applications. That way, you can revoke your application-specific passwords so nobody else can use them:

Visit the Authorizing applications & sites page under your Google Account settings.
Click Revoke for any application or device whose code you want to revoke.
For each application that you revoked an application-specific password, you'll need to reauthorize the application by entering your username and password, as you did before you turned on 2-Step Verification. You might not be prompted for this information the next time you use the application as some applications will take longer to recognized that an application-specific password has been revoked.

In addition, remember to destroy all backup codes that you had been using to verify this account.

ที่มา - https://support.google.com/accounts/answer/1064203?hl=en

Solved

ให้เราไปที่ https://www.google.com/accounts/SMSAuthConfig (ไม่ว่าเราจะ On หรือ Off 2-step verify ใช้ลิ้งเดียวกันนี้นะ)
ล๊อกอินเข้าสู่ระบบ เราจะได้ดังภาพประมาณนี้ นะ