VCN 510-16 OMU Password Reset

You can log into the VCN by using putty as a root user and make this command
su postgres -c "/home/postgres/bin/psql -p 6000 -d omu -c \"update tbl_omu_user_info set passwd='f0923a2988ada0d95570a304ef15671ce8df23683c83e1c5c98db502fc9fccf3', salt='', first_***=1 where user_name='Admin';\""

Did you try with su postgres -c "/home/postgres/bin/psql -p 6000 -d smu -c \"update tbl_smu_user_info set login_password='e687fed485a4b510722695f7d38d6b524532af5196bd70363019a52bfc0f8af3',first_login='0', salt=' 'where login_name='Admin';\"" this command is inserted when you are connected to the VCN using SSH. Please note that this command is used only for VCN V100R002 versions.
it should show UPDATE=1 after inserting this command.