Google Sync Known Issues with iOS
Here are the current limitations for usingGoogle Syncon AppleiPhone, iPad, and iPod touchdevices.
Incorrect or invalid password
You might need to unlock your account by solving a short CAPTCHA.
If you use 2-Step Verification (2SV) or single sign-on (SSO) with a third-party identity provider, you need to use an Application Specific Password. For details, seeSign in using App Passwords.