It's been brought to my attention that there is some SSL mismatch between the PayPal and my forum.
If you encounter the SSL error after the payment (while returning to forum). Please check the URL and remove :80 in it and then click the reload page button on error.
It looks like this:
forum.wpe.tv:80/group[...]
Remove the :80 from the URL, so it looks like this:
forum.wpe.tv/group[...]
That solves the SSL protocol error.