How did Nazi Germany lose so much land during 1944?

During 1944 Nazi Germany had increased the size of it's Army with new recruits from Germany and the rest of Nazi-Occupied Europe. It also produced new armor and aircraft and equipped it's men with the latest advancements in technology. However, in the summer of 1944 during operations such as Operation Overlord and Bagration huge numbers of men and material were lost (40 divisions destroyed in just those two operations). Could you tell me in detail what factors caused these huge losses in land, men and material?

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia��).