I have recessed lights in kitchen. I placed LED lights in them several year ago, spot/flood screw in. I just replaced all five with the updated, lighter weight, technology. When I hit the switch all lights came on. Click it off and two of the lights did not come back on. Checked the socket/light by placing the old but working light back in and the light came on. Concluded it was a bad light...but tow of the? Took back to Lowes and exchange for two new lights. Place the two exchanged new lights in the sockets did not work. Took the non working light swapped it with a working "new" light and it worked. So lights are good, sockets are good as the old lights come on in the sockets. The only thing I can observe is the contact point on the new lights is slightly wider and the actual contact point is slightly recessed more than the old LED's. Any suggestions?
My bet is that the middle contact isn't sprung enough to be consistent.
First, turn the breaker off.
Then, gently tug at the central contact in the middle of the light fixture's socket to bend it a tiny bit further forward. Needlenose pliers can work well for this.
Don't bend it too hard; otherwise you'll have a broken light fixture to deal with.