DTLS handshake failed: Error in the push function

[Fourhundred Thecat]

Hello,

when I connect with openconnect, I am getting these errors:

DTLS handshake failed: Error in the push function.
(Is a firewall preventing you from sending UDP packets?)

the connection works, but I suspect the firewall is blocking udp packets

Can I et rid of the error messages?
Can I, for instance, specify to connect tcp only?