Car randomly wont start I've had my battery and alternator checked both are working fine

Does everything come on in the dash like normal but when you go to start the car you get one loud "CLICK" from the engine area? If so, you might have a weak ground in the engine area or check your battery terminals for corrosion. trace each wire, + to the fuse box and check for corrosion (white/greenish powder), negative to the body and then engine/trans and look around the rest of the engine bay for wires connected to the car body. take off the fastener and clean with scotchbright or a soft wire brush, wipe clean, reassemble. Please come back and give feedback on other symptoms, solutions, etc.