Nighthawk MR60/MS60 Satellite not syncing with router

Hi All,

I recently bought a Nighthawk MR60 from one of my known and it was working perfectly fine in her house. I got into a weird problem. Satellite is not syncing with the router (it's not weird yet). I tried to factory reset both router and satellite multiple times but that didn't help. Finally, by chance, I tried to connect one of the satellite with ethernet cable router and then it synced perfectly. And to my further surprise, it synced second satellite as well which was placed there wirelessly. After that I tried few other combinations like removing ethernet cable once sync is complete (blue light), change the firmware to older version but nothing else worked. So after spending around half of my day, my current setup: router (MR60) is wired to one of the satellite(MS60) and 2nd satellite is without wire and they are working good. But this is not the ideal setup (pls correct me if I am wrong since this is my first Mesh setup). 

As far as I know and the videos that I watched on youtube, both the satellites should work without any ethernet wire. 

Router Model number is: Nighthawk MR60 

Firm ware version on router and both satellites is: V1.0.6.102_2.0.45 (which is upto date)

Can you please guide me what I am doing wrong? Or any pointers to fix this issue?

TIA