MailChimp. Error 401 (Unauthorized) when sending a request for adding a new list member

Here is how I'm trying to send a request:

fetch('https://us17.api.mailchimp.com/3.0/lists/185415c92c/members', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'Authorization': 'anystring:8ec49e64f2041073d3fe56e0abc5fe5f-us17',
      },
      body: JSON.stringify({
        email_address: 'email@mail.ru',
        status: 'subscribed',
      }),
      mode: 'no-cors',
    })

And I get such error:

POST https://us17.api.mailchimp.com/3.0/lists/185415c92c/members 401 (Unauthorized)

What am I doing wrong?