STM32L011F4 power consumption

Hi team,

i need your help, i use STM32L011F4 controller ,This controller consuming 2mA current in sleep mode, as per datasheet it consumes only a less than 0.5mA current in sleep mode,

i can use only a I2C and RTC peripheral with 16MHz frequency.....

sleep mode function is

 HAL_PWR_EnterSLEEPMode(PWR_MAINREGULATOR_ON, PWR_SLEEPENTRY_WFI);

please help me how can i configured the controller? and how to reduce the power?

Thanks

Krishna