Gemini API Free Tier — all projects Restricted / generateContent 403

Hello,

All Gemini API projects associated with our Google Workspace account are now shown in Google AI Studio as:

Billing Tier: Unavailable
Status: Restricted

AI Studio displays:
“This Project’s API access is restricted. Please set up billing to continue.”

API authentication works and models.list succeeds, but generateContent returns:

403 PERMISSION_DENIED
“Your project has been denied access.”

One affected project:
Project ID: gen-lang-client-0458606..

The Workspace account had previously been temporarily suspended by Google security systems, but it has since been restored and secured with 2-Step Verification and a passkey.

Could a Google team member please advise how to request a manual review of the Gemini API account/project restriction?

We would like to continue using the eligible Free Tier.

Thank you.