Error while using group by clause

Column 'tblSales.Salary' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.

select ts.SalesmenName,ts.Age,sum(tp.Quantity) as Quantity

from tblSales ts

inner join tblProduct tp on ts.SId=tp.SId

group by tp.SId,ts.SalesmenName,ts.Age

Output :

SalesmenName        Age   Quantity 

 Rajesh             26      3
 Mohan              24      2