unable to login into sm web client ESS login

Hi,

one new person has newly joined in our organization, his Windows AD/Domain ID is "PeterPaul"

he is able to login to the windows login, but if he uses the same user id and password in HP service manager 9.40 web client login as contact users/ ESS login, he is getting message as invalid username/password, please try again.

I tried checking his name in HP SM 9.40 admin login > operator>contact searched as "PeterPaul", it said "no records found" refer the screenshot as attached.

The LDAP service is already enabled and rest of the several windows AD/Domain users are able to login in HP SM .40 web client easily.
How to check and troubleshoot this case.