{
    "status": 500,
    "source": "https://default-web-....azurewebsites.net/api/ContactsList,
    "message": "The format of value '*; q=.2, */*; q=.2' is invalid."
}

public class APITest {
public static void Attempt(){
    HttpRequest req = new HttpRequest();
    Http http = new Http();

    req.setMethod('GET');
    req.setEndpoint('https://microsoft-apiapp....azurewebsites.net:443/api/ContactsList');

    HTTPResponse resp = http.send(req);
    System.debug(LoggingLevel.INFO, resp.getBody());
}}