If you do not add ''/guacamole'' to your url, you will see a blank page since you did not specify which application in Tomcat you wanted to access.
You can also The safest and most secure method to access Guacamole is using [https://www.amahi.org/apps/openvpn OpenVPN] and an [[OpenVPN_clients|OpenVPN client]] from a smart phone, tablet, or computer.