[Q] G2 won't charge topic

i have an issue with g2 d802.
sometimes it won't charge the phone.
it shows the lightning icon on the battery, states the device is plugged to AC charger, but it won't charge.
i'm using LG original charger & cable, also tried other LG original charger and the results are the same.
on my other device, G3 its working fine both chargers.
i've done factory reset->doesn't help.
rooted the phone and installed G3 ROM-> doesn't help
and sometimes when when trying to power on the device it shows a yellow warning sign with the battery icon .
any ideas??
help please...