Gemini API suddenly returns “Your prepayment credits are depleted” despite remaining Cloud Prepay balance

[Jimin]

Hello,

My Gemini API worked normally until about a week ago.

Current situation:

• Billing Account: Cloud Prepay 019B84-D4EBE2-85EF09
• AI Studio Tier 1
• Gemini API usage over the last 90 days is only about KRW 3,000
• Cloud Billing still shows approximately KRW 13,000 remaining balance
• AI Studio Billing shows KRW 0 credits and no transaction history
• API requests now fail with:

429 RESOURCE_EXHAUSTED
Your prepayment credits are depleted

The same API key and project worked normally until last week.

Could you please verify whether this is related to the recent AI Studio Prepay billing migration or whether my prepaid balance is not being recognized correctly?

Thank you.

[davide.segullo]

I have the same problem, it seems to be related to a new change introduced by google, if you’re in tier 1 and 2 now you can only pay using prepay method, if you wanna use postpay method you must be tier 3.

But it’s weird because I can’t find any official announcement

[Dabee]

Try setting up prepay in the AI Studio Billing menu. I happened to come across a warning message in the Spend menu, and after setting up prepay accordingly, it’s working properly now.

[Pooja_Kapse]

Hello everyone,

I’m not certain from your message whether your existing balance is in credits.
If so, you’ll need to make a small prepayment to activate the prepayment account and use the credits.