Dear Maintainer,

    * What led up to the situation?
I attempt to send an email with a large file attached.  I have an
account with Box and I have previously successfully sent large
attachments using this service.

    * What exactly did you do (or not do) that was effective (or
      ineffective)?
When I attach the file I get a message saying "This is a large file.  It
might be better to use Filelink instead."  I click on Link and I get a
message "Your file is being linked.  It will appear in the body of the
message when it's done."

    * What was the outcome of this action?
A rotating symbol appears next to the file name in the attachment box.
Nothing else happens, however long I wait.

Checking with Box they referred to an earlier Mozilla bug
https://bugzilla.mozilla.org/show_bug.cgi?id=1021684 which is marked as
resolved.  Apparantly "Mozilla's response was that the current
Thunderbird version 33 beta may be built on the current API calls."