JWT auth/validate error code 24 and no user found message

JWT.io
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1

Hi,
When i login from my woocommerce mobile app, successfully return the jwt but when validate, it show this error,

{“success”:false,“data”:{“message”:“User not found.”,“errorCode”:24}}

What should i do, here is my code

login()
  {
    const headers = new HttpHeaders({
      'Content-Type': 'application/x-www-form-urlencoded'
    });
    const userData = `username=${this.username}&password=${this.password}`; 
    return new Promise((resolve, reject) => {
      this.http
        .post(`https://myurl.com/?rest_route=/simple-jwt-login/v1/auth&`, userData, { headers })
        .subscribe(
          res => {
           console.log(res);
            const auth = `JWT=${res['data']["jwt"]}&AUTH_KEY=myauth`;
            return new Promise(resolve => {
              this.http
                .get(
                  `https://myurl.com/?rest_route=/simple-jwt-login/v1/auth/validate&JWT=${res['data']["jwt"]}`
                )
                .subscribe(res => {
                console.log(res);
                });
            });

            resolve(res);
          },
          err => {
            alert(JSON.stringify(err));
            resolve(err);
          }
        );
    });
  }