At the time of your review we have over 20,000 active installs so the plugin definitely works.
Oftentimes when a merchant is having trouble connecting they’re trying to connect to a personal PayPal account rather than a PayPal business account. If you manually entered your API keys and are having issues you most likely entered an incorrect value which is a simple fix.
Instead of leaving a review which isn’t very helpful, I recommend creating a support ticket here where we can assist you.
Reviewing the site that’s linked in your WordPress profile, I can see you’re using our plugin and it’s working as expected. It looks like you were able to connect the plugin so an update to your review would be appreciated.