DELL Latitude 5590 does not start with new RAM memory

Hello Everyone,

I have a problem with my DELL notebook after RAM memory upgrade.
8GB, 2400MHz DDR4 RAM was installed originally (Hynix). It was one stick installed in A-DIMM slot.
It works perfectly.
Now, I've installed 2x16GB 2666MHz DDR4 RAM from Kingston and notebook doesn't want to start.
After click power button only LED error code blinking.
The error sequence is 2-3 (2 amber, 3 white). I've checked that it is "No memory / RAM detected" fault.
I've tried install only one stick at a time (in one and the other slot alternately) and it was the same fault.
Then I've disconnected the BIOS battery for at least 1 min and reconnect. After this, when I've turned on the notebook again, I've seen another error code - 2-1 (2 amber, 1 white). It means "Possible CPU Failure".

So I've removed Kingston memory and installed original RAM stick (Hynix). The notebook booted up and works fine (as before).
I've tried install Kingston memory again, but only one stick together with original RAM stick.
Tested configurations and results:
1. original RAM in A-DIMM slot and new RAM in B-DIMM slot -- The notebook doesn't work - error code 2-3.
2. original RAM in B-DIMM slot and new RAM in A-DIMM slot -- The notebook works fine. RAM was detected and 24GB capacity is reported in BIOS and in the system.
In second configuration I've checked both sticks of Kingston RAM and both are fine.

As soon as the Hynix memory is removed, the laptop stops working, and reports 2-3 fault code.

Is it possible to use only new Kingston RAM in 2x16GB configuration? I know that the CPU and MOBO support 2400MHz RAM frequency, but it this a problem? I assumed that faster RAM could run slower without any problems.

PS
All memory sticks changes were made with AC adapter and battery disconnected!