Some of these machines have reset stats on the top of the heater box. Remove mains plug, take of the top and look on top of the cast alloy box along the top of the machine. If you can see one or two small stats at the front and rear of the box with a little red plunger in the middle, press down on this and if you hear a distinct click you have reset the safety cut out. Reasons for this device tripping are many, switching off whilst still hot, blocked or faulty fan or ducting etc. If it does not have this type of stat then the only way forward is to use a multimeter or similar to test the element, stats and wiring.
That which can be asserted without evidence, can be dismissed without evidence.