slime block still does not push

Put the summary of the bug you're having here

What I expected to happen was...:
Describe what you thought should happen here
Slime block to be pushed
What actually happened was...:
Describe what happened here
I pulled the lever and the stick piston did not push it
Steps to Reproduce:
1.place sticky piston facing slime block
2.place lever beside sticky piston
3.pull lever