Offline bulbs

Hello i month ago i purchace 2 mi led lamps and i have a lot of issues … First of all in my mobile phone (lgv20) i had installed the app Xiaomi Home , and i relise that i have disconnections and i must put username and password … My router ZXHN H108N sometimes can see the lamps in dhcp list , but the most of the time the lamps cant open in squedule program . Is there any solitioin for this issue ?