What's the problem when dashboard information center says "Check charging system?" on 1999 Oldsmobile Aurora

Car sat idle for 5 weeks. Started + ran. Dash lights went out. Shut down. Thanks!

Asked by for the 1999 Oldsmobile Aurora
Simply enough - the charging system has failed, and needs to be diagnosed and repaired. The most common cause of failure is a defective alternator. Have a diagnostic test performed.
To DaveJHM,
Thank you! Your answer confirmed what I had thought. Again, thanks!