Page Isn't working

Page Isn't working

Hi Dears
In the user groups when i set more than about 25 requester to the user group,the preview doesnt work and show me Page doesnt work instead of showing list of users.
How i can solve this issue?
is it my problem and i have to use more than one user group or its a public problem from servicedesk plus?
Thanx
              New to ADManager Plus?

                New to ADSelfService Plus?