Why was Roosevelt’s first charge up San Juan Hill not successful?

Included among the U.S. ground troops were the Theodore Roosevelt-led ... El Caney was not secure, some 8,000 Americans pressed forward toward San Juan Hill. ... behind because of transportation difficulties, led the charge up the hills. ... regiments were the first up Kettle Hill, and San Juan Hill was taken soon after.

answer; /// i believe the correct answer is general act charters;