I've encountered the same problem as Sven N. (https://bugs.launchpad.net/ubuntu/+source/openconnect/+bug/1754601/comments/24), with the same Ubuntu 20.04 and OpenConnect version v8.05-1. After a few minutes, the "SSL read error" and "HTTP/1.1 101 Switching Protocols" appear reproducibly, connected clients hang or abort, and I had to cancel and reconnect.
What helped for me was switching from
$ sudo openconnect --protocol=pulse ...
to
$ sudo openconnect --juniper ...
Which is odd, because my company's VPN is Pulse Secure?!
I've encountered the same problem as Sven N. (https:/ /bugs.launchpad .net/ubuntu/ +source/ openconnect/ +bug/1754601/ comments/ 24), with the same Ubuntu 20.04 and OpenConnect version v8.05-1. After a few minutes, the "SSL read error" and "HTTP/1.1 101 Switching Protocols" appear reproducibly, connected clients hang or abort, and I had to cancel and reconnect.
What helped for me was switching from
$ sudo openconnect --protocol=pulse ...
to
$ sudo openconnect --juniper ...
Which is odd, because my company's VPN is Pulse Secure?!