Paypal Pro: Inconsistent numbers of paid subscribers

There is an inconsistency with the number of paid subscribers on my site. On the site, there are 4,736 premium users but when I pull the number of subscribers from Paypal, it’s only about 3,800, which is about 900 difference.

While there are some subscribers that I applied premium membership to without Paypal subscription, it can’t be more than 100.

I checked some of the accounts. Some who have already canceled their subscription on Paypal still have access to premium content on the site. I thought that if someone cancels their subscription directly on Paypal, their account on my site would be automatically updated.

Any ideas on how this happened? Also, what would be the best way for me to check which premium accounts on my site have active subscriptions on Paypal? There’s a total of over 10,000 members here.

Thanks.

https://www.ads-software.com/plugins/s2member/