what should the flashing light in back of modem color be?
Are you referring to the lights where the LAN cable connects? If so, the lights indicate the connection and what the speed the ports are available to provide (not the actual service, just the port). Green is higher speed, amber is lower speed. They're both often on (if separate), depending on the device. When blinking, it means data is being transferred.
I'm sorry, I was meaning their modem, VIASATS modem. I thought at one point it was green when my router is attached to their unit, it's now yellow/amber. I'll have to try another cable because I know I had it green at one point, I just have to learn to leave my darn cables alone!!!! Thank you