Maybe you can get out of the loop by using the guacamole menu (CTRL-ALT-SHIFT):
https://guacamole.apache.org/doc/gug/using-guacamole.html#guacamole-menu
Could you post the connection settings you used to check if they are correct?
Thanks, I am going to check.
EDIT: A copy/paste error. I tried to upgrade to guacamole 1.1.0 to make Swiss German work and took some code from mattermost but no success so far, see Howto install guacamole - #98 by mrmarkuz
The package in the repo is not affected.