Someone else had this on here recently. You are likely not getting a good connection between the
tank and the base.
I assume you are using the GS Air tank that came with it. Thoroughly clean the magnetic connector and check to see if the coil is screwed it correctly. Also try and clean the connection on the mod by pushing some paper towel down in the well.
If you have a similar tank like an evod or protank 2 mini, you can try that with the other ego magnetic connector.