Hello! The problem you're experiencing is most often caused by a software glitch on the Arris products, but there's always a chance that the wireless capabilities of the router have failed.
You may have already tried this (and let me know if you have): unplug power to the Arris router for about 1 full minute, and then plug it back in and let it boot up. Once it has, check for connections again on your phone and see if the wireless name for your Arris router appears.
If it does, you should be back in business! If it does not, please let me know and we'll dig in further.
Thanks! I look forward to hearing back from you.