[stunnel-users] stunnel5 to stunnel4 not work

I'm working on openvpn over stunnel. My configuration can work with windows and linux. both are stunnel4. But it never work out in android. I have ubuntu18.04 and set as stunnel4 server side. I try to get connected with android stunnel: SSLSockshttps://github.com/comp500/SSLSocks/releases/tag/0.0.17-beta, which should be compiled with stunnel5. It simply not work. I got "NETWORK_EOF_ERROR" time to time. If I remove stunnel tunnel, it will just work. So I think it's stunnel5 to stunnel4 issue. But how to avaoid such issue?

Best Regards Robin