Can not install centos 7 on Dell EMC R750 xs server

Hi I am zaheen Noorani . I am A support Engenner  in a hospital . here  is a server which has dell emc r750xs . we use a customized software , that was openMRS+ . The software run only centos 7 operating system . in this server centos 7 can not install . we are try our best , but can not success  . so please helps us.