TM1Web Integrated login problem since office relocation

[jed]

Last week integrated login both in Perspectives and TM1Web was working fine.
Over the weekend we have had an office relocation.
Integrated login in Perspectives is still working but not in TM1Web. I've double checked all the IIS settings and the Web.config file to ensure that nothing has changed. I've completed an server reboot, iisreset just in case. I've also tried the old delete the client user and recreate. Still not working in TM1Web.

Interestingly, if I log onto the server via RDP and try to access TM1Web on the server, integrated login does work. This makes me think that the issue is somehow network related but I'm not sure where to look. I am going to contact IT to investigate but I know they will say that nothing has changed on the network and it will be up to me to find a resolution.

The error message received on the client is attached.

So has anyone got any ideas of where to look??
cheers
jed