So, you come back a day after to complete another one of those good, yummy quests you're just so fond of. But, what's this?! You go to log-in and it says that there's no user with the email or username?! What in the ****.
Righty right, I understand. But, if you're reading this, then you're wanting an answer to this. Well, here's the solution.
When you go to Forge of Empires, there are different servers assigned. Find the server you signed up with(You'll find this at the top bar of the web browser their website). If you don't know which one you used, just look for the one in your region, and so on.
However, if you STILL can't figure it out, or if trying to find it is too much of a headache, then go to your email and find the FoE mail that ask you to "validate your e-mail address". At the bottom of the mail, there's a button labeled "Confirm E-Mail Address", click it.
There, it should automatically log you in. But before you click play, look at the Server you're logged in (found at the top of the screen).
However, if all fails-- contact the staff there at FoE.