Excel export over https doesn't work

Clicking on Excel view gives the error message:

Microsoft Excel cannot access the file 'https://sdev.sil.org/sdev/jira/secure/IssueNavigator.jspa?view=excel&tempMax=1000'. There are several possible reasons:

? The file name or path name does not exist.
? The file you're trying to open is being used by another program. Close the document in the other program, and try again.
? The name of the workbook you're trying to save is the same as the name of another document that is read-only. Try saving the workbook with a different name.