Error: Unable to connect to remote server.
This error occurs when the Central server cannot be reached when launching Transaction or Query due to the internal network connections.
Check whether the central site is reachable via Browser from the same system where this issue is reported. You can check the Internet connectivity from the command prompt like below.
Step 1: Open your command prompt via Run > Cmd and press enter.
Step 2: In the Command Prompt, enter the command as Ping > 127.0.0.1 and press enter to check the connection.
Also reach out to your internal IT team and ensure whether the network connections are up and running.