Horde export option not showing .mbox or .eml filetype options



In the past when I have exported folders from Horde, I was given the option to export as .mbox or .eml. ; those options are no longer there.


The two options that I have are 'Download into a MBOX file' and 'Download into a MBOX file (zip compressed)'. If I choose either of those options, I get the following File Not Found  message:


File not found

... can’t find the file at https://mydomain.com:2096/cpsess3962482541/horde/services/download/?app=imp&actionID=download_mbox&m....

    Check the file name for capitalization or other typing errors.
    Check to see if the file was moved, renamed or deleted.


Can you suggest a fix or a work-around?