Playing as Altarians, I have been able to colonise some settle-able planets with my colony ships and then it becomes pot luck whether I can colonise. The colony ships are directed to a planet then close to 1-4 moves to the planet, the ship stops. When selecting again the ship to go to the planet, the ship refuses to recognise that it can move there with no pop-ups saying why. Sometimes the ship can settle another planet but understandably very frustrating at the moment when everything is going well but pot luck with settling planets!