CSRF Failure when Updating License using Dashboard

Hi, I am exploring Tyk on-premise in my Ubuntu 16.04.

I followed the Dashboard installation tutorial here until the bootstrapping part. The Dashboard initial license key prompt works fine, and I can access the Dashboard.
However, when I want to update the license in the Nodes and Licenses section, I got “CSRF failure” error after submitting the form.

Did I miss something that caused me to get such error?