Website slow even after WPFC enabled

Dear WPFC team

I am using the WPFC version in the last few years and I would be thanking you for such wonderful plugin you created. Recently I am facing some issues in the last 1-2 months. My blog has become litle slow. I have not added any new plugins in the last 3 months. The blog home page was loading in 1 to 2 seconds when I checked on webpagetest.org or pingtoom tools. However, now it is taking 6-7 secs to just load home page. For posts, it is loading higher than this. Can you pls check and let me know what settings I need to update ? I am attaching the webpagetest result for your reference. https://filebin.net/meto2m9pw54jbfce/slow.jpg?t=om1y9oh1

The page I need help with: [log in to see the link]