I don't think you did anything wrong. Weak soft skill sounds like an excuse. Their circumstances may be shifting dramatically. For example, a big customer might have just notified them that orders would be reduced in the near future.
Employment in the U.S. is at will. They have the right to let you go.
Cheer up! Is there anything you can do to revert that decision? I don't think so. Move on and you're gonna to have a better offer.
