ODK Briefcase push failure


I have made a survey on kobo with an encrypted XLS form. I have pulled it using ODK briefcase v1.15.0 succeffully and can push and export some of the data but not all of it.

When I try to push I get this message:

Preparing for upload of form definition with 0 media attachments
Uploading form definition with no media attachments
UPLOAD FAILED: Form definition upload failed. Detailed error: BAD REQUEST (400) while accessing: https://kc.kobotoolbox.org/non_williams/formUpload
Please verify that the form definition that is being uploaded is well-formed.
retrieving next chunk of instanceIds from server…
retrieving next chunk of instanceIds from server…
Partially successful upload…

Support questions about Kobo should go to the Kobo team at http://help.kobotoolbox.org