Active Directory / Domain controller

Hi,

I wonder if anyone can shed some light onto a problem we seem to have created.

We have an office LAN of 192.168.5.0/24 due to recent growth and a new building we have increased our subnet 192.168.4.0/23.
For example I put my machine on 192.168.4.100 I am no longer able to connect to exchange, network shares are no longer there.

I can ping and RDP onto the domain controller so connectivity is there, I have added the new range into AD sites and services so we have them both now 192.168.4.0/24 and 192.168.5.0/24

Has anyone got any ideas to why we seem to have lost connectivity to the domain.

Thanks in advance