Power BI embed Azure SQL direct query error Couldn't load the schema for the database model Couldn'

Yes but the code i am using does not take db connection string

       public DashboardController()
        {
            this.workspaceCollection = ConfigurationManager.AppSettings["powerbi:WorkspaceCollection"];
            this.workspaceId = ConfigurationManager.AppSettings["powerbi:WorkspaceId"];
            this.accessKey = ConfigurationManager.AppSettings["powerbi:AccessKey"];
            this.apiUrl = ConfigurationManager.AppSettings["powerbi:ApiUrl"];
        }

        public async Task<ActionResult> Report(string reportId)
        {
            using (var client = this.CreatePowerBIClient())
            {
                var reportsResponse = await client.Reports.GetReportsAsync(this.workspaceCollection, this.workspaceId);
                var report = reportsResponse.Value.FirstOrDefault(r => r.Id == reportId);
                var embedToken = PowerBIToken.CreateReportEmbedToken(this.workspaceCollection, this.workspaceId, report.Id);

                var viewModel = new ReportViewModel
                {
                    Report = report,
                        
                    AccessToken = embedToken.Generate(this.accessKey)
                };

                return View(viewModel);
            }
        }