I'm assuming that you are working with a layout view since you are reporting that you see the "Legend" item in the Contents pane. I'm also assuming that you have added the legend to the layout page (Add a legend—Layouts | ArcGIS Desktop). Are you seeing the legend display on the layout view? Could you provide a screenshot?
If you've added a legend to the layout and legend items are not drawing there may be a legitimate reason for this. The data source of your geocoordinates layer may not support a legend. What is the source of your layer?
Another reason legend items might not draw is that there are no features visible in the map and the Only show features visible in the map extent is checked on for this particular legend item (layer). For more information see Work with a legend item—Layouts | ArcGIS Desktop. Legend items are members of the legend. You can find them listed in the Contents pane underneath "Legend".
Of course, there could also be a bug with the software. We would need more information (steps and data in order to reproduce the issue) to make that determination.
Hope this helps,
PS - In case you are unsure about Printing or Publishing your map I've have a few links below that you might find informative.
Hi @TomBole, just found a new reason that caused the legend stop showing up, FYI.
The layer data source is Oracle geodatabase, but the user account is locked on Oracle side, so the map can list data in attribute table, but refuse to show the legend on map.
Thanks for the information, however, I'm not familiar with Oracle database locking. I wouldn't even know where to begin troubleshooting this. Can you contact Esri Support? They are better equipped to handle troubleshooting steps and gather bug data. They can be contacted at https://support.esri.com/en/contact-tech-support.
Thank you @TomBole for your response. This morning I got legend not displaying problem, then did some research and found this post. Tried all the suggestions that you listed, but later I figured out that for my case it is caused by Oracle account locked, after unlocked the account my problem is solved . So just post my experience here and for reference to others just in case who will get stuck in same problem.