extended web application cannot be edited by contributors, and only from one computer

Hello,

I have recently UN extended a web application that had been working correctly. I did this in order to change the host header.

After re extending using a new host header, the application / site collection can no longer be edited by contributors; Only the owner can edit, and even then, only from one specific computer.

Permissions seem to be set the same, structure and content are the same -

Any suggestions/thoughts?

Thanks,

Troy

Troy