Power BI Export to file Error

/////// Export sample ///////
        public async Task<string> PostExportRequest(
            Guid reportId,
            Guid groupId,
            FileFormat format)
        {
            var client = GetPowerBiClient(); // new Power BI client instance
            var pages = client.Reports.GetPages(groupId, reportId);
            var powerBIReportExportConfiguration = new PowerBIReportExportConfiguration
            {
                Settings = new ExportReportSettings
                {
                    Locale = "en-us",
                },
            };
            var exportRequest = new ExportReportRequest
            {
                Format = format,
                PowerBIReportConfiguration = powerBIReportExportConfiguration,
            };
            Export export = null;
            try
            {
                export = await client.Reports.ExportToFileInGroupAsync(groupId, reportId, exportRequest); // this never returns
            }
            catch (Exception ex)
            {

            }

            // Save the export ID, you'll need it for polling and getting the exported file
            return export.Id;
        }

Here's my full function. 
Do I have a double await?