New double oven is 4wire and manual allowed neutral and ground together for a 3 wire connection. Previous oven was installed using the same method. However the oven no longer turns on, including the lights. Wires were tested and are still “hot” I replaced the breaker (yes both are 40s). Connections are sound. I’m curious if issue can be the subpanel, which is fed with 3 wires and has the ground and neutrals bonded. I’ve read this can be an issue but also read it’s not an issue if the incoming line is 3 wire. Thoughts on possible causes?