Failed to enroll key in UEFI Secure Boot for sled 15 sp3

SUSE Linux Enterprise Desktop SLED Install-Boot
1

Hi team
I want to inset a third part driver in SUSE Linux Enterprise Desktop 15 SP3 of virtual machine. So I need to import a self-signed key to the system.
My steps as following:

  1. sudo openssl req -new -x509 -newkey rsa:2048 -keyout MOK.priv -outform DER -out MOK.der -nodes -days 36500 -subj “/CN=Test/”
  2. mokutil --import MOK.der
  3. reboot system and entoll MOK key as https://sourceware.org/systemtap/wiki/SecureBoot
    But after above steps, I find the the MOK key isn’t enrolled successful. the enrolled list should empty.
    sled15sp3:~ # mokutil --list-enrolled
    MokListRT is empty