Ralat 'Dapatkan token akses kosong' semasa menjalankan kod contoh latihan msgraph-sdk-go

func (g *graphhelper) initializegraphforappauth() error { clientid := os.getenv("client_id") tenantid := os.getenv("tenant_id") clientsecret := os.getenv("client_secret") credential, err := azidentity.newclientsecretcredential(tenantid, clientid, clientsecret, nil) if err != nil { return err } g.clientsecretcredential = credential // create an auth provider using the credential authprovider, err := auth.newazureidentityauthenticationproviderwithscopes(g.clientsecretcredential, []string{ "https://graph.microsoft.com/.default", }) if err != nil { return err } // create a request adapter using the auth provider adapter, err := msgraphsdk.newgraphrequestadapter(authprovider) if err != nil { return err } // create a graph client using request adapter client := msgraphsdk.newgraphserviceclient(adapter) g.appclient = client return nil } // this part works, and i get the apptoken with required scope, once decoded. func (g *graphhelper) getapptoken() (*string, error) { token, err := g.clientsecretcredential.gettoken(context.background(), policy.tokenrequestoptions{ scopes: []string{ "https://graph.microsoft.com/.default", }, }) if err != nil { return nil, err } fmt.println("expires on : ", token.expireson) return &token.token, nil } // the getusers function errors out func (g *graphhelper) getusers() (models.usercollectionresponseable, error) { var topvalue int32 = 25 query := users.usersrequestbuildergetqueryparameters{ // only request specific properties select: []string{"displayname", "id", "mail"}, // get at most 25 results top: &topvalue, // sort by display name orderby: []string{"displayname"}, } resp, err := g.appclient.users(). get(context.background(), &users.usersrequestbuildergetrequestconfiguration{ queryparameters: &query, }) if err != nil { fmt.println("users.get got error", err.error(), resp) printodataerror(err) } resp, err = g.appclient.users(). get(context.background(), nil) if err != nil { fmt.println("users.get got error with nil", err.error(), resp) } return resp, err }

Users.Get got Error error status code received from the API  error: error status code received from the API code: InvalidAuthenticationTokenmsg: Access token is empty.Users.Get got Error with nil error status code received from the API