Extrnal API access. Status_code 414
You'll have an easier time modifying the permissions from within CiviCRM - Administer menu &gt;&gt; Users and Permissions &gt;&gt; Permissions (Access Control).  When changing permissions from WP, you're usually dealing with machine names, not human-readable labels, so it can be hard to correlate error messages with the particular permission needed.
It sounds like your REST user still doesn't have the Access CiviContribute permission.