Benoît

[storm hound]

Hi there!
Can you share the ID (req_xxx) of the failing API request?
https://support.stripe.com/questions/finding-the-id-for-an-api-request

[lapis raptor]

Hi, thanks

The ID is req_RgSp3wYxwyzMSv

My item has 3 quantity, and i asked to give him 5

[storm hound]

You need to pass the subscriptionItem id

https://site-admin.stripe.com/docs/api/subscriptions/update?lang=python#update_subscription-items-id

If you want to update an exeisting plan of a subscription

[lapis raptor]

Ah, ok

Perfect, it worked ! Thank you !