Here's why:
* "Convene" means to gather or assemble formally. It's typically used in the context of meetings or other organized events.
* "Scheduled" implies that the meeting has been planned and set at a specific time.
* "At meeting" is not a complete phrase and doesn't convey a clear meaning.
Examples:
* "The CEO will convene a scheduled meeting to discuss the new product launch."
* "We need to convene a scheduled meeting to address the recent budget concerns."