Why is axios get request not working?

Question

JSON Web Token

Hello everyone, I've been working on a problem for two days now.
The bottom line is, I send a request from the Restlet Client to the server and get a 200 response, everything works fine. But I'm trying to send an axios request through REACT, writes

Access to XMLHttpRequest at .....
Uncaught (in promise) Error: Network Error
    at createError (createError.js:17)
    at XMLHttpRequest.handleError (xhr.js:80)

Here is the react code:

validation_token() {       

        var urlValidation = 'localhost:8000/api/GetTokenData';
        var token = this.getToken();

        var headers = { 
             'Token': token
        };

        axios.get(urlValidation, {  headers  })
            .then(Response => Response.json())
            .then(json => {console.log(json)});
    }

I just want to output to the console what comes there.
PS: The header is Header set Access-Control-Allow-Origin "*" on the server - I wrote it directly in htaccess. If not, then the restlet client would not work.