It can happen that in some cases the water is not transmitted to the pods even if the wick is in a correct position. This may be due to hard water build-up or root matter growing through the wicks - in this case you should replace the wicks for new ones. For this you would need to remove the wick from the tube and then insert new ones.
If you need any help on how to exactly change the wicks in your plastic cup, then we've got a nifty guide for you here:
You can also try to push the wick out with a thin object, like a pencil, and then insert the new wick.
New wicks are available on our spare parts page: https://clickandgrow.com/collections/smart-garden-replacement-parts