Crontab deja dup issues

[dahouse7 <dahouse7 gmail com>]

Hi,

I've been trying to get deja-dup to run scheduled backups via crontab.
Basically, I want deja dup to run every morning at 8am.
I've created the following cron entry.

0 8 * * * deja-dup --backup

Unfortunately, it never seems to run. I can easily run deja-dup from
the command line, but it doesn't work from cron.

Could anybody help me clear this up?

Thanks