When attempting to update a node’s uid field using Drupal’s JSONAPI, the following error occurred:
This was resolved by changing the permissions.
Specifically, the issue was resolved by enabling the Administer content checkbox under Node.
However, please note the following warning that was displayed:
Warning: Give to trusted roles only; this permission has security implications. Promote, change ownership, edit revisions, and perform other tasks across all content types.
I hope this serves as a helpful reference.