Seems there are a lot of you playing out there, so in result a new server has been added. See the post by SmokeJumperPS here that includes explanation for server lights as well.

We recognize that Emerald was overloaded. Therefore, we just spun up a second east coast server, Konried. Feel free to play there. Explanation of server lights: Teal lights = 0 - 3000 population (750 people per light) Yellow lights = 3001 - 4000 population (250 people per light) Red lights = Over 4000 people.