I have an on-premise confluence instance on which I've installed the Lucidchart plugin (not the on-premise Lucidchart plugin).

We restrict outbound internet access from the server which results in this error:

"The Lucidchart plugin was not able to communicate to the Lucidchart servers. Your Confluence server is most likely on a network that does not allow outgoing traffic on port 443. To use the Lucidchart plugin your network administrator will need to allow outgoing traffic over SSL on port 443. If you are not able to resolve the issue by updating your network configuration please contact support@lucidchart.com for additional help."

Can anyone tell me what the URL/IP Address is that the plugin is trying to call out to?