Here are your parts
Replacement parts for KEBC177KBL0 models | AppliancePartsPros.com

Here is a manual which should be a close match to yours
https://secured.whirlpool.com/Service/SrvTechAdm.nsf/2cd44500d572193285256a45004fd9d6/6342e2edf7772b6e852573440054cfc6/$FILE/4317418%20Single%20Wall%20Oven.pdf

The first thing to check is the power.
The lights, control panel etc. all run off half the line while the lements require the full 240 volts.

Try flipping the breaker off/on slowly a couple times, sometimes you can loose half the line without actually tripping the breaker.
If this does nothing, check the voltage at the plug
L1 to L2 should be 240 volts
L1 to Neutral and L2 to Neutral, both should be 120 volts.
If OK
Unplug the unit and check the wires at the terminal strip in the machine to make sure none are loose or burned out
If OK
Check the power at the terminal strip.
Be careful as 240 volts is lethal !!!

Next would be the over heat thermostat, Item 37 in Section 1.
It is not uncommon for these to pop after a self-clean cycle.
Remove power from the unit and the wire to one side of the thermostat.
Then measure it with a meter, should be 0 ohms.