Configure to modem.... How

Looks like it may be a router as well (only looked at a picture of the unit on Amazon with no details listed).

Is this "Calix 716GE-I" new to your network or have you been using it for a while? Do you have any other devices that are able to connect to the network (other PCs, phones/tablets)?

Try to create a new network location in macOS to see if the default settings for a new location allow you to connect.

Try creating a new admin user. Log into the new admin user to try connecting to the network.

Try booting into Safe Mode as well.

It never hurts to try an SMC Reset or a PRAM Reset (Ihold the PRAM reset for at least three chimes or a full minute on 2017 and earlier Macs). These resets are only for Intel Macs.

What is the exact model of your Mac and version of macOS? You can get this information by clicking the Apple menu and selecting "About This Mac".

If you are using any anti-virus apps, cleaning software, or third party security software, then these items may be interfering. If you have any of these apps installed, then uninstall them by following the developer's instructions. These types of apps are not needed on a Mac and usually cause more problems than they solve plus they impact system performance.

You may need to configure the modem/router as well or at least check its network configuration.

Is this a Cable Modem with router or just a plain cable modem? If it is just a plain cable modem, then you need to reboot both the cable modem and the Mac in order acquire an IP address from your ISP.