Error: Loading field graph for 'message' failed with status 500

I am running a fresh installation of Graylog and am trying to setup widgets for my Cisco ASA dashboard. I follow instructions on the blog to enable analysis of messages. However, attempting to generate quick values for the same generates the above error.

Please assist.

quick values might not be possible on the different data you have in the message field. That is the reason this is disabled by default.