Cant unlock bootloader or go to download mode in Smasung M11

I have Samsung M 11 (SM-M115F/DS). I want to install TWRP in it. But I cant unlock boot leader or go to download mode. I already enabled OEM Unlock. I saw in some sites that in this device i have to press both volume up and down to go to download mode or unlock bootloader but actually nothing happens. It only goes to recovery mode with power and volume up. There it has a "Reboot to Bootloader" option. enter image description here when i go there i get this enter image description here. When i give the option start i return to recovery mode.