SetVariable from UEFI RuntimeServices is not working as expected

I was implementing an approach to keep an incorruptible file using authenticated variables as specified in UEFI, i want to create two time based authenticated variables. For preparing the payload data to call the SetVariable properly, i used the sbvarsign tool 0.9.2.

My code just worked fine when i was testing using the Open Virtual Machine Firmware(OVFM) from EDK2, the authenticated variables was created as expected, but when i try to use the same on my Inspiron i15-3567. i always get a Security Violation return from the call to SetVariable.

The following is the first lines of output from dmidecode:
Getting SMBIOS data from sysfs.
SMBIOS 3.1.1 present.
Table at 0x000ED050.

Handle 0x0000, DMI type 0, 26 bytes
BIOS Information
Vendor: Dell Inc.
Version: 2.9.0
Release Date: 01/17/2019
Address: 0xF0000
Runtime Size: 64 kB
ROM Size: 16 MB

I managed to run the UEFI Shell and ran the command ver, to get the UEFI implementation version. I got the following output:
UEFI v2.40 (American Megatrends, 0x0005000B)

The SetVariable does a lot of verifications before create and set an authenticated variable, and as my code is running fine on the reference implementation i need a help to troubleshoot the problem. Should i contact AMI or Dell technical support? I can provice access to all the code im using too.

Regards.