OK.
Enter the UEFI diagnostic test environment of your notebook. Power button--> immediately tap the Esc key to invoke the startup menu. Choose F2 in the startup menu selection. Select the component tests and then choose memory. The following image is just examples of what you will see.
Is your notebook still in warranty? warranty status check
Memory modules are a warranty replaceable item.
If you have more than one module you can find out which one has failed by removing the modules and putting one in the slot closest to the systemboard. Power up the notebook and run the memory test on the module. If that one passes then turn off the notebook, remove the module and put the other one in its place and test it as well.