I have a Synology NAS server that has a L2TP/IPSec PSK VPN Server running. I used to connect to it with my Android phone (Version 7) (and previously with my iPhone) just fine. Whether I was on 4G or on a Wifi, it always connected without problems.
I have recently replaced my Android phone with a new one (Huawei P30 Pro) that runs on Android 9. The strange thing here is, that I can connect to the VPN when I am on a 4G network, but when I try to connect to the VPN when I am on a Wifi connection, it does not work and comes back with an unsuccessful message.
I am pretty confident that it is not the Wifi network, as I can still connect to the VPN with my old phone side-by-side, but the new one is not working.
Is there any way to troubleshoot the VPN connection to figure out where the problem is? Is there any log files I can check on the phone? Or do you have any hints why that could be?
Thanks for any hints.