The bellow gasket in my machine needed to be replaced which my husband was able to do. After he put the machine back together, the door won’t lock keeping the washer from running. We took it apart and checked all the connections. It comes on but won’t start. Help!! The laundry is piling up. Can anyone point us in the right direction to troubleshoot? 
This would suggest there is a problem with either the door lock assembly, the wiring to it or the control unit. See if there isn’t tech notes inside the lower service panel or under the top which will tell you how to test components.
The most likely explanation is that the wiring to the door lock or the assembly itself was damaged in replace the gasket (this is easy to do, I have done it myself) so you might want to try replacing those items.
If all this doesn’t work please post a model number and we can see what else it might be.