Translation:This is a serious problem.
No. It should not be accepted. I am surprised no one has objected to this suggestion. 严重的 is used to refer to the severity of an issue. It simply cannot be paired with a 'question'. A serious question refers to a question that's important and not meant to be taken lightly. The difference is actually quite significant. Please do not mislead people if you are not a native speaker and do not fully grasp the nuances.