It's early evening here (Ireland). The Sun is definitely set, and there is a bright half Moon. However there are no stars or planets visible at all, anywhere in the sky. There is no cloud, at least nothing substantial, the Moon is perfectly bright, no sign of cloud in that part. There are low level street and house lights, but I don't think that's what it is. Stars and planets are usually well bright enough to see on a generally clear night. Any clues?