Hi! It could very well be that you set up your external website to use HTTPS. Sadly, the WebStats plugin cannot use HTTPS to provide the statistics. If you really can't use plain HTTP, you can set up a reverse proxy as described on the wiki:
https://github.com/Dantevg/WebStats/wiki/FAQ#https.
If your website is not served over HTTPS, there is some other problem. Either way, I'd be happy to help! Just post on the discussions page or open a Github issue. (in general, reviews are not a good place to ask for help, because I don't get notifications)