Why did albert speer stop the production of Landkreuzer P 1000 Ratte?

Albert Speer, the minister of armament and war production in Nazi Germany, stopped the production of the Landkreuzer P 1000 Ratte because he deemed it impractical and a waste of resources. The massive tank was too large and would have required tremendous amounts of materials and manpower to construct, which would have been better utilized for more effective weapons in the war effort.