Consulted some in-house guys.
1. If using hostname, it needs to be fully qualified, try IP instead.
2. 6 minutes is more than enough to cause a failure, change the time.
3. Disable IPv6 and remove the check for Prefer IPv6 over IPv4
4.Make sure Domain and DNS are configured
5. Change this http://<device-IP address>/diagnostics/NTLMSecurity.dhtml
6. Get a wireshark trace, in this case you would need 2nd level support though, so you would need to call in most likely.
7. Curse louder, then report back again.