Hello Michael,
Thank you for your message.
Authorization: Custom Server Security (both check-boxes On)
Please try to sel ect the
Auto option in the Authorization tab in connection properties. If you have both
Custom server security and
Single password enabled as your authorization method, with the
Auto option enabled the Viewer will use
Custom server security, because it goes before
Single password security in the
priority list.
In order to enable Auto please do the following:
1. In the main Viewer window right-click on the remote connection and choose
Properties.
2. Navigate to the section
Authorization and in the dropdown menu choose
Auto.

Also please clarify if your server is located in the same LAN as the Viewer or Host and if you use the server's external address? If this is the case, please try using its internal address to connect within your LAN.
Single Password Security on, but do I even need it for not LAN connections?
Single Password is one of the authorization methods. You must authorize on a remote Host regardless of connection type. Here's a related article on
authorization methods you can choose fr om.
Also, it's not necessary to use the RU server as a
relay server and the
Custom Server Security simultaneously. For example, you can use a
direct connection and still use a Custom Server Security as the authorization method.
Of course, the server should still be directly accessible for Viewers and Hosts.
Please let me know if you have more questions.