Chromecast and Motorolla MG7700 cable modem

Writing this down in case someone else experiences the issue.

I recently bought a Motorolla MG7700 cable modem to replace our Xfinity xFi Advanced Gateway (XB6). I configured it to use a single SSID for both the 2.4ghz and 5ghz frequencies and right away we noticed that our 1st generation Chromecast started having connectivity issues. We could stream videos from our phone but the pause and fast forward controls would immediately stop working. After about 15 minutes of video the Chromecast would always error out. Afterwards, there was no way to reconnect to the Chromecast without factory resetting it.

To solve the issue we gave dedicated SSID’s for the 2.4ghz and 5ghz frequencies. The Chromecast uses the 2.4ghz and ever since the two frequencies were given unique SSID’s, it’s worked flawlessly. This was an important lesson that it’s safer to manually choose which frequency to connect a device to instead of relying on the magic of the router doing it for you.

Strangely, our previous Xfinity XB6 gateway also used a single SSID for both 2.4ghz and 5ghz frequencies and our Chromecast worked fine so there is something off with the Motorolla modem in that regard.