You can power cycle the modem by unplugging it at the wall outlet or the power brick (NOT at the back of the modem), waiting at least 30 seconds, then plugging it back in. It may take about five minutes for the modem to be fully up and running after plugging it back in.
It might also be good to power cycle your ATA, as well.
If after power cycling you're still having issues, it would be best to start a new topic in the Tech Support section to get help in getting the issue fixed.
Ryzen 5 3400G | MSI B450M Pro-M2 MAX | 16GB Corsair Vengeance DDR4 3000 | XPG SX8200 Pro 512GB NVMe | Windows 10 Pro