'Unable to connect to server' error when starting client
on 14 August 2020 09:41 PM
Tip: If you’re seeing mysterious behavior with the User Client, but not getting any error messages, check to see if the User Client has been configured to use the —silent option, which suppresses all error messages. Try running the client without this option, and see if the client then gives you any useful error message information first!
Note: if you’re seeing this message, but you know that it’s not able to connect because you’re not on the same network as your server, then take a look at the Suppress Error Notifications when offline article. This applies if e.g. you take your laptop home with you, and you don’t want to be bugged with ‘unable to connect’ messages.
Check to see if the App Server is started, and if not, try restarting the App Server.
Check the config.properties file to make sure that the server-ip and server-name lines are correct. They should show a valid IP address and hostname for your Application Server. If you’ve recently migrated your PaperCut server then you’ll need to update the connection details for the clients.
The local copy of the
Ideally you’ll have a static IP address set up for your Application Server, so that the connection details remain the same.
If you’re using a Firewall in between clients and the Application Server, take a look through the Firewall Ports page to see what ports need to be opened for PaperCut to work.
As a test, open a browser Window on the client and try navigating to http://<server-name>:9191 and https://<server-name>:9192. If this doesn’t work, try opening these ports on the firewall or disabling the firewall on the server altogether as a test.
If you’re running Windows, double check the Windows Advanced Firewall rules to make sure that the network profile (Domain/Work, Private, Public) of the network interface matches how the rule is configured. We have heard of situations where a server is restarted after Windows updates and suddenly the network type switches from the Domain Profile (less restrictive) to Private Profile (more restrictive) and the different Firewall rules prevent the PaperCut client from connecting.
There’s more information here on Forcing SSL, however if port 9192 or 443 isn’t open, or if you don’t have a trusted certificate installed, then the client won’t be able to connect. A good test is to navigate to https://<server-ip>:9192 from the client, and make sure that you can connect without any certificate errors before checking this box.