Hello NMontiex,
Please make sure that you are using valid and identical parameters for server address when starting server and nodes instances and in the client GUI preferences on the Network tab.
If you have still problems, please provide the screenshots of the commands used for starting server/nodes and of the Network preferences tab to support@agisoft.com, in case the information contain sensible data. If there's nothing confidential in the server name/address and rott path, you can post the requested information here.