Based on below Jenkins documentation description , I am using comma separated Id's to get email .It only works with one Id which is my employee Id for a project. If I add another employee Id separated by comma it doesn't work. below are the paramters

input message: "Do you want to approve this job to deploy to QA?", submitter: "897656,783425"

submitter (optional) : User IDs and/or external group names of person or people permitted to respond to the input, separated by ','. If you configure "alice, bob", will match with "alice" but not with "bob". You need to remove all the white spaces.