Pyhocagui as compiled 2015-01-25 has an outdated set of kex options, not supporting sha2. As a consequence, connection to modern servers is not possible (rejected by sshd).
A recompilation / binding to current libraries should suffice I think. The latest x2go client works, for instance.
Who could possibly please help with this?
Dr David P Kreil
Telephone: +43 660 9899903
Office: +43 660 9899900