How to add a used book on Amazon using the SP-API

Question

I've been trying to do this for about two years now. And I read that at that time (2021) not all types of products were yet available/working correctly. I'm trying to add a book, with this code (for marketplace germany) . But specifically when trying to list a used book, I get the following error: 'code': '4000003', 'message': 'The specified product type is invalid or not supported.', 'severity': 'ERROR' Although the category for supported books is absolutely correct "ABIS_BOOK". I can list other products. Has really nothing changed in 2 years, or am I doing something wrong? If this isn't a bug, what is it?"

I really need your help, any kind at all, please.

import requests
import json
from creds import credentials

token_response = requests.post(
"https://api.amazon.com/auth/o2/token",
data={
"grant_type": "refresh_token",
"refresh_token": credentials["refresh_token"],
"client_id": credentials["lwa_app_id"],
"client_secret": credentials["lwa_client_secret"],
},
)
access_token = token_response.json()["access_token"]

endpoint = "https://sellingpartnerapi-eu.amazon.com"
seller_id = "XXXXXXXXXX"
sku = "SKU1234"
marketplace_ids = ["A1PA6795UKMFR9"]
attributes = {
"condition_type": "UsedGood",
"marketplace_id": marketplace_ids,

}

response = requests.put(
f"{endpoint}/listings/2020-09-01/items/{seller_id}/{sku}",
params={"marketplaceIds": ','.join(marketplace_ids)},
headers={
"x-amz-access-token": access_token,
"Content-Type": "application/json"
},
json={
"productType": "ABIS_BOOK",
"requirements": "LISTING_OFFER_ONLY",
"standard_product_id": {
"type": "ASIN",
"value": "3776621478"},
"attributes": attributes
 }
)
res = ListingsItems(credentials=credentials, marketplace=Marketplaces.DE)
print(response.json())