If you come across an error, you should be able to find it here. If not, file an issue because it's unintentional.
The framework has already started, you cannot create any new providers, create new hooks, add paths, or run start again.
An init function errored somewhere, the message is provided in the error.
There was an issue adding the module to the load stack, which means a simple require caused an error.
The type you are passing to a parameter of some sort is invalid.