Hi, I have been having issues with my DECO's losing internet. - I have NBN FTTC, the NBN device appears to be connected.(this device has also been power cycled.) - The red light is Flashing slowly on

For now, I have my Fiber modem as main router and 3 deco M5 as access point to wifi connections. I had to disable deco M5 as main router cause I can't do anything with ipv6 enabled on it, lose connect

After I install firmware 1.4.4 all my Decos keeps loosing connection between then. I was so happy with my Decos, but now It's a headache. I am in quarantine, couldn't leave and my decos are not workin