Hi @karwas,
OJS should give the IPN URL to PayPal, but perhaps they now require it to match (I haven’t tried this recently). It should be…
http://.../index.php/myJournalPath/payment/plugin/Paypal/ipn
(…replacing ...
and myJournalPath
with the relevant values.)
Regards,
Alec Smecher
Public Knowledge Project Team