I have a house that was built in the 50s. It came with mostly two prong outlets. About half of these outlets tested positive for being grounded and have bare ground wires in them. When updating the outlets to a standard three prong outlet and attaching the bare ground wires to the green ground screw I am now getting “open ground” on the tester. I have retightened the ground wires and am at a loss what what to do. Due to the current COVID orders in my state I won’t be able to get an electrician to evaluate the wiring for a few weeks. So what do I do?