The Issue:
The Regus network blocks IP phones. The "DHCP VLAN" option must be enabled to get around the Regus network settings.
The Solution:
To enable the DHCP VLAN option on a Grandstream Phone
1. Press the center button on a Grandstream phone (pictured above).
2. Navigate to System >Network >IP Settings >DHCP.
3. Enable DHCP VLAN.
4. Reboot the phone.