Thanks for the quick response.
Error reporting was already set to "system default." I tried changing it to various levels, and that made no difference.
I turned on debugging under "system" to see if there would be additional information, but when I did that, the page was completely blank, with nothing, not even an error message.
If it is any help, I am attaching a screenshot of what I am seeing.
Please let me know if you need any additional information. Just so you know, I am running on Joomla! 3.9.15 Stable with PHP Version 7.2.27.
I am using Joomshaper Helix Ultimate template, but I also tested the Library under the basic Beez3 default template. The result was a bit different in that more of the page showed, but the error message with the same with a bit more detail in saying the page could not be found. I am also attaching that screenshot.