If the leakage comes from the transparent tube, it may not fit the place well. Please disassemble the transparent tube by turning and pulling it back from the black part and assemble back again.
There is a seal between them and it will fix the issue when you assemble them back well.
1) Remove the tube by turning it counterclockwise.
2) Check inside of the grey part that remains attached to the body.
3) There is a washer inside. Please make sure that it is properly fitted.
4) Put some vaseline or dish detergent to the end of the tube and put it back in by pressing firmly.
5) Fill the tube and check again.