WOO authorisation / permissions error

Error:
Invalid signature - provided signature does not match / Sorry, you cannot list resources.
Error Ugyldig signatur - oppgitt signatur samsvarer ikke / Beklager, du kan ikke liste ressurser.

Description:
Linked2 uses the OAuth standard to authenticate your WooCommerce API key & secret. A pre-requisite for this to work is you must be using >=WordPress 4.4 and this plugin by the WordPress REST API team must be installed & enabled:
https://en-nz.wordpress.org/plugins/rest-api-oauth1/