Yeelight Sunflower connection timeout

I have 3 Yeelight Sunflower light bulbs. control box is wired to the router via LAN cable. First day of installation everything was working fine. Now I cant connect to the control box via the Sunflower app on my iPhone 6. Have tried resetting, doesnt work. Cant control the light bulbs via the app as the app times out when connecting to the control box. Everything on the same wifi network.

Version number on the control box says 2.1.2. Please help

Help please?