Why German shore guns struggled against the D-Day bombardment fleet

Why didn't German artillery in the 88 to 120 mm range counter-battery the destroyers bombarding Normandy on D-Day?

The destroyers had radar, heavy firepower, and support from cruisers and battleships. Many German positions were already plotted and suppressed before they could engage effectively.

German artillery in the 88 to 120 mm range faced destroyers carrying four- or five-inch guns. The destroyers had the support of the wider bombardment fleet. Light cruisers could answer with six-inch guns, while destroyers could deliver a heavy volume of radar-directed fire. Many German positions had already been plotted, and positions well placed for counter-battery fire were among the first targets for suppression. Battleships added fourteen-, fifteen-, and sixteen-inch shells against the more dangerous positions. Even without that heavy support, the ships are judged to have had some ability to withstand the four- or five-inch shellfire they expected in combat, giving them an advantage over exposed artillery positions.