I tried https://<ip_address> which turned into https://<ip_address>/esm_login.asp?loginBannerDisplayed=1, there I logged in as system, when I clicked on System Administration Tool I could log in to ESM. If I clicked to Server Manager, https://<ip_address>/server-manager opened with a login screen showing "You are not authorized to access this area.".
I also tried to open directly https://<ip_address>/server-manager and tried to log in as system/admin but with no luck.