Intermittent disconnection using mwan3

Good day Sir and Ma'am!

I am using Openwrt to handle vlan, adblocks and mwan3 for my little business. My device are OrangePi one and Newifi D2(WRT firmware).

My OPi handles the IP assigning and lease times depending on the value of their vouchers. I think my OpenWRT device causes the issue because whenever it happens I can't open the LuCi but I can still access Opi which is connected via Vlan. I have to restart the router so that my Opi could detect my internet again.