An application (like an email or chat client) or a mobile device recently tried to sign in, but couldn't verify it was really you. To prevent unauthorized access to your account, Google notifies you via email and/or SMS about this type of suspicious sign-in attempt.
How to help secure your account
Check your account's security information and activity to make sure no one besides you has attempted to sign in to your account.
- Check your recently used devices.
- Check recent security events.
If a sign-in, app, or device looks suspicious to you, click Secure your account and follow the instructions to help re-secure your account.
If you think we mistakenly blocked an attempt that was you, you can allow access to your Google Account or sign in using App Passwords.
If you don't want to receive these notifications on your phone, change your security notification settings.