I tried to setup pppoe over openvpn tap. When my windows client connected openvpn and pppoe. There had packet lost at server.
Here is a pcap comparison of vpn server and client.
Here are pcap files.
pcap.zip
Here are config files for server and client.
openvpnconf.zip
BTW, I also tried linux client and it work normally.
thank you for your help