Tested in android and it seems to me that it is not supported. The client is stuck waiting for the server to respond to a push request. I assume the client is the problem . I did a brief search and it seems to me that it is supported only on desktop app (windows and MacOS), I did not see any positive result on the mobile front.
Here the logs
09:50:09 openvpnserver[8037]: 130.223.148.213:47916 PUSH: Received control message: 'PUSH_REQUEST'
09:50:10 openvpnserver[8037]: 130.223.148.213:47916 PUSH: Received control message: 'PUSH_REQUEST'
09:50:12 openvpnserver[8037]: 130.223.148.213:47916 PUSH: Received control message: 'PUSH_REQUEST'
Do the mobile platforms even have an app “community edition”? I do not see anything like that in google store.
Edit, I found the answer, the “community edition” for Android is the app maintained by Arne Schwabe. I will test it for the 2FA functionality when I will find the time. First, I want to finish the howto part, including iOS. I will keep updating the document here.
Edit 2: also Arne Schwabe app failed to ask for the TOTP token, I guess it is not yet implemented