Accessing FIM Portal after NLB

Experts,

I have installed FIM Portal on two servers. Sharepoint farm but different.

I am able to access FIM Portal on addresses

https://server1.domain.com/identitymanagement
and
https://server2.domain.com/identitymanagement

All works well. Now when i configured NLB and made a common URL https://company/identitymanagement.

https://company/identitymanagement is not accessible. I always keep asking password but does not login.

Kindly suggest.

Thanks,
Mann