TC8305C & Gateway IP Address

Hello:

Today, a client had their TC8305C gateway factory-reset and wiped out their entire local network, including all settings.  I have been able to regain access to the gateway; however, in the past, I have been able to change the local IP address of the TC8305C.  Now, when I log onto the TC8305C, the last box of the gateway's local IP address is grayed-out, indicating that it is no longer editable.  Well, always in the past, this last box (quadrant) was editable and this entire local network was configured, as such.  Now, if we cannot edit this last local IP quadrant, the entire network is unreachable.  Has anyone experienced this with their TC8305C?  Does anyone know of a way to make the TC8305C's local IP address fully editable, namely that last (fourth) quadrant, such as in 10.0.0.xxx or 192.168.1.xxx? 

Anyone's help and/or assistance would be greatly appreciated; thank you!  I look forward to hearing from others.  🙂