How to properly call and implement ConnectyCube's External auth via Custom Identity Provider

Question

I'm trying to implement Custom Identity Provider of ConnectyCube.

The instructions are:

I am now trying to implement the last step:

POST https://api.connectycube.com/login
login=IP_user_token

I try to do the above by the following code:

const login = {
        login: token,
      };

      try {
        const {data} = await axios.post(
          `https://api.connectycube.com/login`,
          login,
        );

        console.log('data', data);
      } catch (err) {
        console.log('err while calling api.connectycube.com/login err', err);
      }

When I do that though I get the following 403 error:

[Error: Request failed with status code 403]

Am I POSTing incorrectly?

How to fix?