King Alfred

Please help if anyone knows anything I can try. So, the battery us charged, Volt meter says 12.4v. The battery connections are fine. What happens is when I turn the key to start it, there is a click and all the electric shuts off. I go to the battery, turn the connector a little and it comes back on. Go to start it, and as soon as I go to turn the engine over it all shuts off. Repeat. It is not a bad connection because the electricity only shuts off when I turn the engine over. Never had any problem
​Beforer, starter has always been fine. You can turn the ignition to on, all lights, everything works but when you go to turn the engine over, there is a click and all electricity shuts off. Fuses all look fine as far as I see. My jeep is stuck in the parking lot at work so I would love to be able to go get it lol. Only other thing is radio doesn't work now. Idk if that's related.