Could use a little more info, but check this

These guys like to sit level and have all the parts in correctly. Double check that its is mounted level. When you change a filter on them the has to go in the exact way it came out and the plates with the tube have to line up just so. The filter has to also sit level so the water can trickle in the holes on top properly. That top bracket has to be sitting on the filter properly. Hope that helps