avoid poor internet connection topic

Happy new year to everybody.
I just got this on a rooted gpad. Reboot, turn wifi on/off didn't work. I read about resetting to factory device or router. Before doing that, I stuck a static ip/mask/gateway/dns to the device and it worked. (If you long press the essid, 'modify', 'advanced settings'). Does anybody know why this happens? In any case, if anybody has a similar problem, sticking a static ip, you may avoid resetting etc.
Best