Piwik and Open journal Systems pluin communication

I use Open Journal Systems on URL http://thermal-science.tech
and Piwik installation on address: Piwik 3.2.1 › Installation
Since Open Journal Systems does have plugin for Piwik I installed it and entered site ID and address of Piwik installation. But, Piwik always complain that there is no communication and that data are not tracked.
Please advise how to make that work.