The ultimate meaning is they didn’t have dinner. But, it could mean they never arrived at the destination for dinner, or dinner was never served, or that they ran out of time, or got sidetracked. There isn’t enough information to determine exactly what happened.
If this was a conversation I was having with a friend, I would assume something came up that took their attention. They got so involved in something that grabbed their attention that they forgot about dinner or were too late to have dinner.
I am an American English native speaker with absolutely no experience teaching language.