I have written an enrolment plugin for another pay-service then paypal. As base I used enrolment plugin from paypal. It functions quite well so far.
But after upgrading from 3.3.1+ to 3.4.1+ I got a strange phenomena. I am even more confused because on a test system I run in parallel update was no issue.
After update and initiating a test payment (instant pay notification) instead of return value "OK" I got a return "Forwarding. If not automatically forwarded please click link below."
This is only happening on my productive system. Same plugin works still quite well on my test system.
Does anyone have an idea how to solve this issue?
Service Provider is All-Inkl.
PHP verision 7.1.11
MySQL version 5.7.20