Offline problems

Hello.

The last few days my device seems to be permanently offline, no matter what I may do.
All started when one day I lost connection to my WiFi. The same day,I have upgraded the speed of my network and the same evening I lost my WiFi connection.
Of course this had as a result for me to loose connection with my Yeelight bulb.
I managed to resolve the WiFi issue (for which I had to change the IPv4 of my phone) but I’m still unable to connect to my Yeelight bulb. It permanently shows off line, no matter if it’s on or off.

Please help!!!