Regarding this issue of yours could i get a copy of the troubleshoot file of the server and client? It is best to get the troubleshoot file after executing this command on CLI "/etc/init.d/openvpn restart" after that navigate to System > Administration > Troubleshoot and download the troubleshoot file and share it with me via pm.
I need from client and server side. Also are you using public ip address on the server side?
Why are you using .pem files? It would be the ca.crt. server.crt , server.key, and dh2048.pem