Most consumer manuals tell you to type 192.168.1.1 into a browser. The 716GE I is a layer 2 bridge by default. It does not have a default gateway IP address that you can reach via your PC.
If your ISP gave you this model (common with smaller FTTH providers), stop treating it like a generic black box. The manual holds the keys to: calix 716ge i manual
Most people think this is just a fiber-to-Ethernet converter. Wrong. The manual reveals this little guy runs Calix’s AXOS software. It’s basically a mini-computer that can self-diagnose, report signal degradation before you call support, and even reboot specific ports remotely. You’re not renting a modem; you’re renting a smart edge device. Most consumer manuals tell you to type 192