Authentication in the web widget - unable to verify my claims

Greetings,

I have zendesk chat phase 4, so I looked in this document how to authenticate my user:

https://support.zendesk.com/hc/en-us/articles/360022185594#topic_n3q_cvq_4fb

In JavaScript, I wrote:

var webWidget = {};

webWidget.authenticate = {

            chat: {

                jwtFn: function(callback) {

                    fetch("…/GetZendeskJwtToken”).then(function(res) {

                     res.text().then(function(jwt) {

                      callback(jwt);

                     });

                   });

                 }

              }

        };

window.zESettings = {

        webWidget: webWidget

};

And in the endpoint (C# .NET) I wrote:

[HttpGet]

public string GetZendeskJwtToken()

{

var payload = new JwtPayload // just a test payload

               {

                              {"name", "test"},

                              { "email", "a@a.com"},

                              { "external_id", 1 },

                              { "iat", DateTimeOffset.Now.ToUnixTimeSeconds()}

               };

var sharedSecret = "..."; // the shared secret I generated

var header = new JwtHeader(credentials);

var secToken = new JwtSecurityToken(header, payload);

var handler = new JwtSecurityTokenHandler();

var tokenString = handler.WriteToken(secToken);

return tokenString;       

}

However, although JavaScript gets the encrypted token from the endpoint,

When it sends it to the callback:

https://id.zopim.com/authenticated/web/jwt

I get an error:

“failed to validate claims”

What’s the problem? I did as instructed.

Looking forward to your reply,

Alon.