With a new shoe, it could be that impregnating agent residue remains on the shoe. This rubs away over a short time as you walk. If you have not used your shoes for a long period of time it is possible that the surface of the sole has hardened and therefore become more slippery. This is normal. The soles of all HANWAG shoes contain natural rubber (an expensive natural material in comparison to cheaper PU soles). Simply take a wire brush or a fine sandpaper and lightly roughen up the surface, or try going for a walk on a tarred road.