Here at Cookers and Ovens, we get many questions to do with our products, and we are always happy to help. This question, however, is one of the strangest ones we have had in a while, yet we are happy to find the answer.
Due to how microwaves work, you can not make toast in one. To make toast you need radiant heat to make the bread dry out, in a microwave the waves cause the water molecules to move about and vibrate, but this means that they do not escape and cause the bread to dry out and have a rubbery texture. If you microwave the bread for long enough, then this does cause a dry, bread-crumb texture but there is no sign of browning.