Big black rectangle appears after being in the game for a certain amount of time, you can just avoid it by hopping on the base and it will leave eventually. It is meant to be a sign from the dev to "take a break" from the game. If you're unsatisfied with the amount of "enemies" so far, the game can be very uneventful for the first two-ish weeks. I typically use this time to clean the base and stockpile signal/points.