Please ensure you entered a valid Assistant URL (404)

Dear Support,
I just installed the WordPress Plugin Watson Assitant. I created the Assistant (using IBM Watson Assistant Lite) and set up everything related to its capabilities (Actions, Steps, Options etc).
Whenever I try to enter the URL and API Key in the Set Up Chatbot Menu of the WordPress Plugin, it says:

Please ensure you entered a valid Assistant URL (404). Click here for debug information.
{
    "error": "Not Found",
    "trace": "659f9edc-f65b-4c61-a12e-b657d5fd594b",
    "code": 404
}

I don’t feel confident I am using the correct URL and API Key. First, I took these from the credentials created initially when I started seting up my assistant (IBM Cloud). There, the URL is:

https://api.eu-de.assistant.watson.cloud.ibm.com/instances/XXXXXXXXXXXXX

which is not alike the example URL you have in your screenshots of the WordPress plugin (the “XXXXX…” represent my assistant ID)

Then, as I looked up documentation, I wasn’t able to find a list of assistants on the Watson Assistant Tool-Page. Neither can I find “API Details” in the settings of my Assistant. Is this because I am using Watson Assistant Lite?

My questions:
– Am I using the correct URL (see above)?
– Where can I find the API Details containing the correct URL and API Key I need to provide to the WordPress plugin?

Kind regards