Hi @Anonymous ,
Could you please share more details about the error message within your app?
Where do you put your LookUp formula? Within a Label control?
Does the "Data" represents your Salesforce table?
Based on the formula you provided, I could not find any syntax error with it. Please check if the result the DataTable2.Selected.Info_No formula returned could match the values in "Client #" column of your Salesforce table. Also please make sure the data type of the result the DataTable2.Selected.Info_No formula returned is same with the "Client #" column of your Salesforce table.
Please consider take a try to set the Text property of the Label to following:
First(Filter(Data, 'Client #' = DataTable2.Selected.Info_No)).'Client ID Email'
Please take a try with above solution, check if the issue is solved.
If the issue still exists, please consider re-generate a new app based on your data source, then try above formula again, check if the issue is fixed.
Best regards,
