LiteSpeed Admin URL returns 503 error and error log shows “cannot allocate memory”. It is due to CloudLinux unlimited setting change. LiteSpeed Admin runs admin_php as “lsadm” user, normally set as “pmem=0K” in LVE, which means unlimited. However CloudLinux enforced “0K” as real “0” instead of “unlimited”, hence execve() function will fail with “cannot allocate memory”.
Quick fix for this is:
lvectl set-user lsadm --pmem=2G