The error code you are experiencing (DO) is indicating that the door is open on the dryer. If the dryer door is closed , you may have a bad dryer switch that may need replacing or a bad fuse on the dryer. You should also check the power cord on the dryer to be sure the cord is not damaged. There is also a possibility your main control board is bad and may need to be repaired or replaced. To do the necessary checks you would need a volt/ohm meter to check the resistance.
Note: Please use caution when doing a self repair
Since the breaker tripped while the dryer was in use, you may also want to check the breaker to be sure nothing is blown or damaged. It is possible the breaker would need to be replaced. This type of a repair would have to be by a
I highly recommend calling for service so a technician can properly diagnose and repair your dryer.
If you need further assistance you can re-submit your question with a full model number and additional details.