Moto e 2015 xt1521...

Guys... I've a moto e 2015 xt1521...some days before I unlocked my bootloader...and then I rooted it...but it was having some problem...so I locked the bootloader and then too I was able to flash my stock firmware...but now I am stuck in bfastboot menu...I can open my stock recovery...but I am not able to switch on my phone...and em also not able to flash the stock firmware now...it says...(bootloader) Preflash validation failed..

I can't unlock my bootloader as I've forgot to enable "allow oem unlock option" .....can anyone help...please... :(