I had exactly the same problem and added some kit (TEC7) between the protective plastic circle (it is not really a lens) and the enclosure. Make sure the lens is dry and don't push to hard when closing it. I used 2K glue before that, but that didn't keep it watertight. The TEC7 kit (some kind of silicone kit) worked better.
But then the microphone died after a while and I can't get that repaired...