After long facing issues with the new OLED JioFi router(JMR520) I found that the issues is with the Firmware itself. You can go to the nearest LYF Service center to get the firmware updated (It is free of cost ). This should solve the n/w related issues (4G n/w automatically goes) and but the Jio4GConnection issue would still persist.
After discussion with the engineer there, they mentioned that is a known issue and would completely support after approx 2 months via another update.
In case you still want to connect, what i noticed after the firmware update that I can connect to the Jio4GVice after router restart. Once, i go out of the WiFi range and come back, either i see Offline or Connecting. Only after when i restart my router, i can connect back.