The problem could be the fritzbox, my parents also have a fritzbox, and I also have problems with wlan connection, but at "normal" use,
I often have to turn wifi off and on because I don`t get an automatic connection. At home with my D-Link router I don`t have the problem.
I often have to turn wifi off and on because I don`t get an automatic connection. At home with my D-Link router I don`t have the problem.