The green, yellow, red, and gray colors are showing the stability of your network to your MLM2PRO unit. Green:  Very good WiFi signal with very good speed.  Yellow: Fair WiFi signal strength. Video stream may lag or produce a gray flicker on screen. Sim performance may decrease.  Red : Poor WiFi signal strength. May have issues connecting or receive disconnections during use.  Gray : Unusable. Please connect to a different network.