Examples of things that happen that might not be suitable to...

Examples of things that happen that might not be suitable to model as Domain Events: Something technical (a ButtonClicked, ExceptionThrown etc) happened that we want to record or handle, but it is not described in the ubiquitous language of our domain. Something that happened outside of our bounded context. This could a Domain Event in another system or a different bounded context. Requests to your system. These we define as Commands rather than events, since they can be rejected by our system.

www.joshbeckman.org/notes/211653546