WDM 4.8.5 check in

We use the T50 clients with WDM 4.8.5 Workgroup After deploying 45 clients to 7 different subnets I am having issues with new clients.

When I set up the thin clients I set them up in our corporate office. They report to WDM just fine. Then I move the thin clients to a new site and they check in just fine and autocreate a new subnet in WDM. This has worked great for 7 sites.

The past two sites when I am done configuring them and relocate them to a new location they do not check in with WDM after I move them from the corporate office. However they connect to the FTP server (located on the same server as the WDM server) to get the ini files. If I move them back to the corporate office they do check in.

WDM server is statically assigned IP
The ini files are retrieved perfectly from the same server
I can ping back and forth between client and server

This has happened with Netgear and Sonicwall firewalls. We use a site to site VPN connection.
All other office to office communication works fine.

WDM is installed on Windows 7 PRO (not enterprise) I’m not sure if this has anything do do with it. However to rule this out i setup a windows XP box and tried to have the clients report to that and they fail to report as well.

To me this seems to be communication between the sites but everything else works. On the thin clients I can open a browser to the WDM server just fine.

Any help would be appreciated.