My Sub Domains redirect to Main Domain after site copy

Hi there! We recently copied an existing Multisite to a new domain for testing/sandbox purposes and it’s almost working, but we are having one major issue. The sub domains index files are redirecting to the main domain and I can not determine why. If you go to a specific page on the sub domain it works fine, but when you go to the home page of the sub domain blog it’s redirecting…

For example:

blog1.mydomain.com redirects to mydomain.com

but

blog1.mydomain.com/somepage works perfectly

Has anyone experienced this before? The confusing part is that all the fines are coming from an existing multisite install that is working perfectly. As far as I can tell, all the Database entries have been updated to reflect the new domain, but I’m stumped.

Any help would be so very appreciated.

We are using virtually all the WPMU plugins, so if you know of any plug in that could be effecting that, please let me know.

Really appreciate your help in advance!