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.
AMD FX-6100 | Samsung 250GB 840 EVO SSD | Western Digital Blue 500GB HDD | 16GB DDR3-1866 | EVGA Geforce GTX 550ti | Windows 10 Pro 64-bit