The most common culprit is a mismatch between the billing address on your card and what's stored in your Google account. Open the app, go to your payment method settings, and verify the address matches exactly what your bank has on file. Also check that the card hasn't expired and that your bank hasn't flagged the transaction — some banks block contactless or online payments by default.
First, confirm NFC is actually enabled: Settings → Connected devices → Connection preferences → NFC. If it's on but the terminal doesn't respond, try removing your phone case — thick or metal cases block the signal. Make sure the screen is on and unlocked before tapping. Some Android updates reset NFC preferences, so it's worth toggling it off and back on.
If your bank's verification SMS isn't arriving, the issue is usually on the carrier side — weak signal or SMS filtering. Switch to Wi-Fi calling or ask your bank to resend the code. Some banks require you to enable 'international transactions' before a card can be added to a digital wallet.
This isn't a Google Pay bug — the payment processor or your bank is holding the authorization. Log into your banking app directly to see the transaction status. If it's been pending for over 24 hours, contact your bank rather than retrying the payment, which could result in a double charge.