fetch receiving http status 0

Question

I created a small project on webstorm with an html that fetch from my localhost:3340

fetch('http://httpbin.org/get')
    .then(
        function(response){
            console.log("response ok");
            return response.json();
        }
    )
    .then(function (json){
            console.log("json ok");
        }
    ).catch(function(error) {
        console.log('ERROR: ' + error.message);
    });

I can’t figure out the cause of the mistake "Networkerror when attempting to fetch Resource." appearing on the Firefox console. This message doesn’t help me much because it seems to me genetic.

Firefox is updated in the latest version

Someone could show me a way. As I cannot identify the cause of the problem I cannot study a solution.

I managed the file . har to see if I discovered something and I think this is the answer that I have:

"response":{

    **"status":0**,
    "statusText":"",
    "httpVersion":"",
    "headers":[
    ],
    "cookies":[
    ],
    "content":{
        "size":0,
        "encoding":"base64",
        "text":""
    },
    "redirectURL":"",
    "bodySize":-1

}

in advance thank you for the support !

Answer 1

304 isn’t exactly a mistake. It usually occurs when the browser realizes that the requested resource exists in cache, so it "does not" the request and returns the data that already existed in cache.