Below procedure clearly explain why your Spectrum router blinking blue and white.
LED on the router indicates the connection status between the router and the devices that are connected to it. The lights usually indicate the status of the internet, Wi-Fi, Ethernet, and the WPS connection. The router usually needs an internet connection to connect itself to several other devices. The wireless connection may come directly through the cable. It allows in receiving information and transmitting it to the internet.
If the LED indicating the power is off, your router is not receiving power.
Solid green or white- Your router is set for connection
Solid amber- Your router is turning on.
Blinking white. The router firmware is corrupted
Blinking white or amber. Your router is upgrading, or the reset button was pressed.
Off - the Ethernet cable is not connected between the router and the computer.
Solid green or white- The Internet connection is ready.
Solid amber-The router detected an Ethernet cable connection to the modem.
Blinking white- The port is sending or receiving traffic.
Off. The 2.4 and 5 GHz Wi-Fi radios are off.
Solid white. The 2.4 GHz and 5 GHz range Wi-Fi radios are working.
Blinking- The router is sending or receiving traffic.
Off- No USB device is connected, or the Safely Remove Hardware button was pressed, and you can remove the attached USB device.
Blinking- A USB device is plugged in and is trying to connect.
Solid green or white- A USB device is connected and ready.
White or green for GB Ethernet connections, and amber for 100 Mbps or 10 Mbps Ethernet connections.
Off-No devices are connected to the Ethernet port.
Solid- a powered-on devices are connected to the Ethernet port.
Blinking- The port is sending or receiving traffic.
If the router is flashing the colors blue and white, it means the router is trying to connect to the internet and the router is ready to be paired. The blinking in blue and white happens only if you are setting up your router for the first time or if you have pressed the Reset button. If you still doubting why your Spectrum router blinking blue and white, click the call button available on the screen.