Hi all. This is my first post on here but I have been tearing my hair out trying to get an API to work in Alteryx and I'm really hoping someone can help!
I'm trying to set up an API which post invite data to TrustPilot but I'm falling at the first hurdle of the authentication, getting the access token.
https://documentation-apidocumentation.trustpilot.com/authentication
It's an OAuth2 flow and I'm trying to use the password Grant Type.
I've attached the flow I've been using but with the API Key, secret and my login details removed. For the authorization I've used API KEY:API SECRET.
When I run it with these details in I keep getting the following error: Client identifier is required.

I thought the API key and secret would act as the identifiers. Does anybody know what I'm doing wrong here?