Sort not working in Query studio

[Kanag]

Hi all,
         I am unable to sort the columns in Query studio. In FM, "Is Unsortable" property is set as FALSE.

Could you tell me what may be the problem?

Below is the error code:
 
RSV-SRV-0003
 
      The report specification contains an error at line ' 1', column ' 1,698'.
 
 
Thanks,
Kanag