Android 'Couldn't Sign In' to Google — How to Fix It

What it means

'Couldn't sign in — there was a problem communicating with Google servers' (or 'Can't establish a reliable connection to the server') means the phone reached the sign-in screen but Google refused the attempt.
The usual culprits are the phone's clock being wrong, a flaky internet connection, a two-step verification prompt waiting on another device, a mistyped password, or — increasingly — your account expecting the modern phone-prompt sign-in instead of a typed password.
It almost never means your account is locked.

Affected Models

All Android phones and tablets
Common during first-time setup after a factory reset
Often appears when signing into Gmail, the Play Store, or a Google-account-linked third-party app

Common Causes

Phone's date and time are wrong (a wrong clock breaks the secure handshake)
Internet connection is too weak or dropping during sign-in
Two-step verification prompt is waiting on another device for approval
Password mistyped, or autofill is filling an old password
Account has 'security activity' from a new device that needs review on a trusted one
Google Play Services is out of date or has a bug
Phone running an old, no-longer-supported Android version Google won't accept
Custom DNS / VPN on the phone blocking Google's auth servers

How to Fix It

Fix the date and time.

Settings > System > Date & time — turn on 'Set automatically' / 'Use network-provided time'.
A clock that's off breaks Google's secure connection and sign-in fails with no useful error.
This is the easiest fix and a very common cause.
Get a strong internet connection.

Switch to a known-good Wi-Fi network or a strong mobile signal — the sign-in handshake is sensitive to drops.
If you're on weak hotel/public Wi-Fi, try your mobile data, or vice versa.
Reboot the router if you're on home Wi-Fi and other devices also feel slow.
Approve the prompt on another device.

If two-step verification is on, Google may have sent a 'Is it you?' prompt to another signed-in phone or computer.
Open it, approve.
The Android sign-in then completes.
If you don't have another device, choose a different verification method (text code, backup codes) on the sign-in screen.
Try the password manually and slow down.

If autofill is filling an old password from your password manager, type it by hand to test.
Watch for the on-screen keyboard auto-capitalising the first letter, and check the language layout if you use a special character.
Three wrong attempts trigger Google's anti-abuse protections, so type it once, carefully.
Update Google Play Services, then restart.

If you can get past the lock screen, open the Play Store > profile > Manage apps & device > Update all.
Particularly update Google Play Services.
Restart the phone after updating and try the sign-in again.
Turn off VPN or custom DNS during sign-in.

A VPN or a custom DNS that blocks Google domains stops the sign-in from completing.
Turn the VPN off in Settings > Network & internet > VPN, and set DNS back to Automatic in the network settings.
Sign in, then re-enable them if you want.
Use a browser to confirm the account, then retry.

Open Chrome on the phone and sign in at myaccount.google.com.
If a Google security review is waiting, you'll see it there — approve the new device.
Then go back to Settings > Accounts > Add account > Google and try again.
If sign-in still fails on a fully updated Android with the right time and a working connection, contact Google account support; that points at an account-side issue, not a phone problem.

Frequently Asked Questions

Why does Android keep saying 'Couldn't sign in' when my password is right?

The most common hidden reason is the phone's clock being wrong — turn on automatic date and time and try again.
After that it's usually the network: weak Wi-Fi or a router that needs a reboot.
And many Google accounts now expect the phone-prompt method rather than a typed password — when you sign in, watch for a 'Tap Yes on your other phone' message and check the second device.
If you don't have another signed-in device, use a backup code from your account's Security page.
It's almost never that the password is actually wrong if you've successfully signed in to the same account elsewhere.