I have a big problem with connecting to my VPN server from 50% of Android devices. Cannot resolve it 2 weeks with network and android developers
VPN server based on IKEv2 with Charon and Strongswan libs, and it works stable with iPhone devices But on Android devices it fails with error “IKE_SA failed, peer not responding” after 3 retransmits of sending IKE_SA_INIT requests
I tried to gather information what was tested, and some hypotheses we had:
Android app used to connect is problematic: No, it is most popular Strongswan application for VPN connection, that advised by many respective VPN services
Network providers are problematic and cut some traffic: No, because iPhone devices can connect to this VPN through standard settings. iPhone was connected to the same Wi-Fi and was in airplane mode for disable cellular network (I double checked that cellular network was disabled)
Android devices that were on manual tests are problematic: No, because when I am not using Wi-Fi from my home provider, but using wi-fi from my iPhone hotspot the connection is Successful. Also another GooglePlay IKEv2 free VPNs is failed to connect
So based on these 3 points I have a very strange situation. Screenshots of android logs will be attached at bottom, with error connection(through wifi) and success connection(through iPhone hotspot) Also screenshot of VPN server error connection log will be attached
I am android developer, and have network developer in my team, so any additional questions please
Dear developers, please give me some advice on what I can do to test and understand what problem we have? Very need it, because based on this VPN serves android free VPN app will be created
Logs: Error logs #1 Error logs #2
