After doing some cursory searching around, it seems like you're not the only person having trouble with this plugin.
I suggest that you contact the vendor directly: NETAPSYS. It also looks like @Franck Bebel, one of the NETAPSYS folks, has been replying to customers having similar issues.
Hello Atlassian Community! Each month, we run a series of Spotlights to highlight Marketplace vendors and apps that our team thinks this Community would find valuable. In last month's Spotlig...
Connect with like-minded Atlassian users at free events near you!Find a group
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no AUG chapters near you at the moment.Start an AUG
You're one step closer to meeting fellow Atlassian users at your local meet up. Learn more about AUGs