Cannot create cache with client.caches.create() – RESOURCE_CATEGORY_GENAI_CACHE not found

Gemini API
,
1

I’m trying to use client.caches.create() in the google-genai Python SDK to cache a large text-only prompt (~2500 tokens). The goal is to optimize cost and performance by avoiding resending this static context repeatedly. Here’s what I do:

from google import genai
from google.genai.types import CreateCachedContentConfig


client = genai.Client(
    vertexai=True,
    project=credentials.project_id,
    location='global', 
    http_options=HttpOptions(api_version="v1beta1")

cache = client.caches.create(
    model="models/gemini-2.0-pro-001",
    config=CreateCachedContentConfig(
        display_name="aime template test",
        system_instruction="Text-only context for moderation",
        contents=[Part.from_text("Some instructional prompt text")],
        ttl="300s"
    )
)
But I consistently get this error:
500 INTERNAL – ResourceCategoryConfig for RESOURCE_CATEGORY_GENAI_CACHE is not found