Cystats not working after upgrade

I’ve just upgraded my blog https://rimibchatterjee.net/ to 3.1 and everything seems to be working fine. However, cystats, when upgraded and reactivated, is returning null results. It shows my date of first post, average comments, most commented post etc but can’t show any live stats all of which are at 0 and have been since the upgrade. Is it a problem with my feed? I am using the Atahualpa theme, latest version, and an rss2 feed. I tried using google tracker to get stats but google has a problem with the ? in my feed uri which apparently XML does not recognise. Could this also be the root of the cystats problem?