Felenasoft

This is a pretty long standing issue and it's pretty frustrating. For the web viewer, the combo box to choose the time goes from 19:59:59 to 00:00:00, but also, when viewing recorded video, the playback stops at 19:59:59. So we cannot view video from 20:00:00 to 23:59:59

What version of Xeoma do you have? Consider updating to the latest version of Xeoma.

Do I understand correctly that the Calendar in archive playback window in your browser does have times between 19:59:59 and 00:00:00 but when viewing continuously, the playback just stops at 19:59:59?
Is it always the same time, 19:59:59 to 00:00:00?
What happens when you select a time within the 19:59:59-00:00:00 time frame (for example, 20:05 or 22:30) - does it get played back?
Do you get the same issues when viewing through Xeoma Client instead of a browser? If yes, please check that you do not have a Scheduler in that camera's chain set to not work in the 19:59:59-00:00:00 time range, or that your other filter modules do not filter out video at that time (for example, there are no motion events if Motion Detector is used). A good thing to check would be if you even have the recordings from that time frame on disk (see the path to the recordings folder in that camera's Preview and Archive module settings).
If the issue is browser-only, and you have all recordings played back correctly in Xeoma Client, maybe try another browser to see if that makes a difference.