Getting Blank Column While Downloading Excel

Hello ,

I am downloading excel file using  class~method

CL_WD_RUNTIME_SERVICES=>ATTACH_FILE_TO_RESPONSE

but I am getting a blank column at first position(A). All the data are correctly downloaded starting from Column B.

Steps I have done :

1. Get data from App server using Open dataset and populate internal table

2. Convert internal table into string

3. convert string into xstring

4. call the above method

Please let me know where I am doing wrong.

Thanks