It goes out when I let go

It lights, then goes out when I let go of the knob

The flame safety device shuts the gas when the thermocouple does not sense the flame. Ooni's fixes, in order (Essentials Guide):

• Hold the knob in for 5 seconds after it lights (10 in Australia), or 20 seconds when relighting after a flame-out, having waited 5 minutes.
• In wind, let it come from the back of the oven, not into the mouth.
• Reset the regulator (see it will not light).
• Wipe the thermocouple with dry paper towel, or blow it clean, oven cold.
• Still going out: Ooni publishes no flame safety bolt fix for the Koda 12. Contact Ooni support or a gas engineer. Owners report a flame safety device failing after years of heavy use (owner report).