Tiktok LIVE Center preparing download disappearing?

Having an issue downloading a longer replay.
Previously, downloads worked normally. Occasionally, the “Preparing” message would disappear, but trying again would cause the progress to jump forward and the file would eventually download.
Now, the “Preparing” progress starts normally, gets partway through, and then disappears. Nothing appears in the browser’s download list.
Refreshing the page and trying again causes the preparation process to start over, but it eventually disappears again.
Is this a known issue with longer replays? When the preparation message disappears, could the process still be running in the background, or has it failed?
Is there another way to retrieve a replay if the normal download doesn’t work?