First:  ensure your current 4G is one module.  More likely, the system shipped with 2X2.

Second:  skip all "Value" RAM (Kingston KVR, Corsair "Value Select", etc.).  It's generally sloppy-tolerance, cheap memory.

Third:  don't mix DDR3 with DDR3L.  The exception:  there are dual-voltage modules that can run at both 1.35 and 1.5V (Crucial generally sells these).

You likely need a pair of 4G modules -- not just one 4G unit.