with this circuit I got an instead 24v i got an 14v output please provide any modification of this circuit

 

First:
what is the input voltage? (220v?)
24V=output voltage?
Output current?
Isolation or not?
What IC?
Next:
I started to fix errors in the schematic but, without knowing more I can't.

 

Ronsimpson has beaten me to it.
R3 will control the output voltage.

 

If you are asking for assistance, would you at least provide all the information? For starters, the IC part number?