Ok what will be the fault here is the thermal cut out safety thermostat will be tripping out. So once its cooled down it will reset itself and allow you to restart it again.
Now the most common cause of this is the fan motor either not working or not turning fast enough so it gets to hot and that causes the thermal cut out to trip out.
What you need to do is access the top. If its still fitted in place then you need to remove it and then you need to access the top.
You will see a hole on each corner and in there is a screw. They are torx screws (star shapped).
Once you have the top off look on the top of the cabinet and you will see the heater box in the middle.
Remove the top of this and there you will see the heater, blower motor and the thermal cut out.
You may need to remove the complete heater box to access this as on the earlyer models the top didnt come off.
You need to check the blower motor and make sure its not stiff and if you are able to very carefully start it and watch it and see if the motor is running fast. If its sluggish then it needs to be replaced.
But if the motor is running fine then its possibley just a faulty thermal cut out tripping out too early so in this case it will need to be replaced and fingers crossed that sorts it from there.
Check that if you are able to and see what you find from there and let me know.