MP2667 On power No Vsys

Hi,
We have used Mp2667 IC for charging the battery. design as exactly same as the reference design provided by the datasheet.

  1. When VIn(5V) is connected the Charging IC not makeing PPM and Vsys =0v ( Observed 5v at Vin).
  2. after 2 to 3 times power supply reconnect the IC making PPM and Vsys is 5V and working as expected. then if you remove the Power supply and reconnect then its not charging and IC works with only Battery, in order to bring it back to Charging the battery then i need to reconnect the power supply at least 2/3 time as quickly as possible.
    Please advise me whats the problem and solution.