When was D day during WW II?

The German High Command remained fixed on the Calais area, and von Rundstedt was not permitted to commit the armored reserve. When it was finally released late in the day, success was immeasurably more difficult, and even the 21st Panzer Division, which was able to counterattack a bit earlier, was stymied by strong opposition that had been allowed to build at the beaches. The Germans generally fought with their customary energy and skill, despite uneven performance by some units. The Panzer units faced withering air interdiction that reduced their effectiveness, yet they offered glimpses of what might have been possible in way of counterattack, had additional mobile forces like the 12th SS Panzer Division and the Panzer Lehr Division been committed earlier into the battle. Despite considerable Allied material superiority, the Germans kept the Allies bottled up in a small bridgehead for nearly two months.