Ok, so I made it to 2040 in my game, being a diplomatic guy, and an NPR granted me trade access. Pretty much my entire civilian fleet heads into their system to drop off goods. Then I get a message saying they revoked trade access due to worsening relations. The next increment, they blew up all my civilian ships in their system. Could somebody please tell me what happened and how I avoid it in the future? Because otherwise I'm going to have to become the vampire race that just kills everyone it meets.