I just upgraded DFM to 3.1.3. When I look at the DFM portal page, the DFM Device Status says "Cannot retrieve Device Summary. Please see the DeviceManagement.log file for more information" I have looked at the log but I have no idea what it means. Please see the attachment.
Like I said, it may have been a timing issue. The daemons can take up to 30 minutes to fully initialize. Logging in to LMS before that can cause weird behavior.