MuntadherTY,
Additional info: I searched for your device: EnGenius Wifi Router model:esr300, but fccid: A8JESR600
But cannot find any info about this device! It is or: ESR300 or ESR600 cannot be both.
Could you check https://fccid.io/A8J and tell me which device it really is?
Even all in- and outside pictures are there.
As ESR300 is not supported by OpenWrt, the ESR600 is.
On the mentioned site is nothing to find your device and all EnGenius devices are mentioned there.
Can you copy a photo of your label on the device?
DG.