Change Confluence page owner Jira automation

[Asier Vadillo]

Hi everyone!

I am trying to create a page in confluence and changing the owner to the initiator of the rule.

I think the way to do it is making a web request to the Confluence API with the created page id. I have this request:
I know the authorization, endpoint ... are good because just changing {{initiator.accountId}} with any user id changes the owner.

Anyone has any idea why it is not working? If logged the smart value returns the initiator id just fine.

The error that appears is:

Thanks beforehand!