Response in JSON Format alternately functioning

Ok. I finally achieved my goal to get informations from a site and used to fill my fields in Ninox

for Example The formula request for the formula field called

Artist name:

let xDiscogsRelease := Numero;
let url := "https://api.discogs.com/releases/" + xDiscogsRelease;
let token := "xxxxx";
let response := http("GET", url, {
        Authorization: "Bearer " + token,
        'Content-Type': "application/json"
    });
let Artist_Name := item(response.result.artists, 0).name;
Artist_Name

Country:

let xDiscogsRelease := Numero;
let url := "https://api.discogs.com/releases/" + xDiscogsRelease;
let token := "xxxxx";
let response := http("GET", url, {
        Authorization: "Bearer " + token,
        'Content-Type': "application/json"
    });
let country := response.result.country;
country

and so on

 the json format field 

let xDiscogsRelease := Numero;
let url := "https://api.discogs.com/releases/" + xDiscogsRelease;
let token := "xxxxx";
let response := http("GET", url, {
        Authorization: "Bearer " + token,
        'Content-Type': "application/json"
    });
response

indicates that the request is accepted and everything is OK

But as I change the Numeric Field called "Numero" to get informations about another album

 i got an error from the response. 

{"error":"Request has failed: error - "}

but if I wait some seconds and touch the Administration button:

 everything see to works well:

 Has anyone of you met this strange behaviour? Is this connected to a maximum limit of responses which can be get in time limit?

Thank you for you attention