Server doesn't support XML config format. Ancient HTML format is not currently implemented.
After some idle time, OpenConnect disconnects (see #297) and attempts to reconnect. At that point I get an incorrect error message:
Server doesn't support XML config format. Ancient HTML format is not currently implemented.
This is a recent VPN gateway (see attached log) so the message doesn't seem to make sense, the XML config format is supported.
I am not using DTLS, it is not supported by my VPN server (UDP traffic is silently dropped by the firewalls whether the VPN server supports DTLS or not).