Welcome to the forums and Happy New Year, newcomer!
Looking through this;
https://psref.lenovo.com/WDProduct/IdeaPad/IdeaPad_1_15ADA7?tab=spec
and this;
https://forums.lenovo.com/t5/Lenovo...pgrade-RAM-On-My-IdeaPad-1-15ADA7/m-p/5247614
tells me you're at the limit as to how much ram the laptop can and will support, meaning 4GB soldered on and 8GB SO-DIMM in the solo slot.
You could experiment by sourcing a 1x16GB DDR4-2400MHz stick of ram and then dropping it in place of the 8GB stick of ram and see if you're able to get the laptop to POST and boot to OS GUI.
Mind you, you should make sure your laptop is on the latest BIOS version prior to performing the above mentioned experiment/test.
If the stick of ram you pulled out of the laptop is DDR4-2400Mhz, that's the highest frequency the laptop can effectively work with.