Error previewing xlsx

[ocdtrekkie]

I got this trying to test xlsx preview on 0.24.0:

GET /api/preview?url=%2Fremote.php%2Fwebdav%2FTestExcel.xlsx&ts=1582041760000 200 1267.081 ms - -
Error: unoconv: UnoException during import phase:
The document 'private:stream' could not be opened.

Unoconv exited with code 5
    at Unoconv.onerror (/opt/app/server/unoconv.js:66:30)
    at ChildProcess.<anonymous> (/opt/app/server/unoconv.js:56:9)
    at ChildProcess.emit (events.js:198:13)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:248:12)

After this I created a completely fresh Excel sheet, put the word TEST in two different cells and saved it, and got the same error. So Excel preview appears broken, though a Word doc I tried worked pretty well.