The same port 443 conflict would probably happen with OpenConnect because it uses the same port.
Port 443 is already used by lighttpd, which can be changed to 444 by editing /etc/lighttpd/conf.d/30-openssl.conf. Unfortunately, OpenVPN server will still not start because there is check on Port 443 hard-coded in the /etc/init.d/vpn-service script, as described in this thread:
You can work around the problem by editing that script to remove the check and also editing /etc/config/vpn_service to change enabled = 1, then running /etc/init.d/vpn-service start.
If your Brume is behind an ISP router, then another option is to port forward the ISP router WAN Port 443 to the Brume at Port 1194.
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