401 error for POST request using the API in make.com

I am trying to create a new course using an API Post request in make.com. I get a 401 error saying that this user is not permitted to create courses.

Strangely, I can GET course info using the API (same credentials / header info as when using the POST request)

The API-key I use has “read_write” permissions.

What could be the issue here?

This is the input in the make.com module “make an API key auth request” module

[
    {
        "ca": null,
        "qs": [],
        "url": "https://kurse.adlx.de/wp-json/llms/v1/courses",
        "data": "{\"title\":\"My course title\",\"content\":\"My course content\"}",
        "gzip": true,
        "method": "post",
        "headers": [
            {
                "name": "consumerKey",
                "value": "ck_xxxxxxxxxmyConsumerKey"
            },
            {
                "name": "consumerSecret",
                "value": "cs_xxxxxxxxxmySecretKEy"
            }
        ],
        "timeout": null,
        "useMtls": false,
        "bodyType": "raw",
        "contentType": "application/json",
        "serializeUrl": false,
        "shareCookies": false,
        "parseResponse": true,
        "followRedirect": true,
        "useQuerystring": false,
        "followAllRedirects": false,
        "rejectUnauthorized": true
    }
]

This is the output

[
    {
        "statusCode": 401,
        "headers": [
            {
                "name": "server",
                "value": "nginx"
            },
            {
                "name": "date",
                "value": "Fri, 18 Oct 2024 19:22:07 GMT"
            },
            {
                "name": "content-type",
                "value": "application/json; charset=UTF-8"
            },
            {
                "name": "transfer-encoding",
                "value": "chunked"
            },
            {
                "name": "connection",
                "value": "keep-alive"
            },
            {
                "name": "x-powered-by",
                "value": "PHP/7.4.33"
            },
            {
                "name": "x-robots-tag",
                "value": "noindex"
            },
            {
                "name": "link",
                "value": "<https://kurse.adlx.de/wp-json/>; rel=\"https://api.w.org/\""
            },
            {
                "name": "x-content-type-options",
                "value": "nosniff"
            },
            {
                "name": "access-control-expose-headers",
                "value": "X-WP-Total, X-WP-TotalPages, Link"
            },
            {
                "name": "access-control-allow-headers",
                "value": "Authorization, X-WP-Nonce, Content-Disposition, Content-MD5, Content-Type"
            },
            {
                "name": "allow",
                "value": "GET"
            },
            {
                "name": "set-cookie",
                "value": "wp_llms_session_xxxxCookieKeyxxxx; expires=Sat, 19-Oct-2024 01:22:07 GMT; Max-Age=21600; path=/; secure; HttpOnly"
            }
        ],
        "cookieHeaders": [
            "wp_llms_session_xxxxCookieKeyxxx; expires=Sat, 19-Oct-2024 01:22:07 GMT; Max-Age=21600; path=/; secure; HttpOnly"
        ],
        "data": {
            "code": "llms_rest_unauthorized_request",
            "message": "Du bist mit diesem Benutzer leider nicht berechtigt, Kurse zu erstellen.",
            "data": {
                "status": 401
            }
        },
        "fileSize": 148
    }
]

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