The error "An inter-plugin communication error occurred" is displayed when instances of the plug-in cannot communicate with each other. This is usually caused by firewall settings or a VPN.
If you are running Windows on your machine, make sure the port UDP 5670 is not blocked. Therefore, open the Windows Defender Firewall with Advanced Security and go to Outbound Rules. If the port is blocked, create a new rule for UDP port 5670 which allows connections.
If you are on macOS you need to add an exception for your host in your Security & Privacy Settings. This can be done either manually from the System Preferences or - if you uncheck the "Automatically allow ***" options below - the firewall will prompt you upon the first launch.
(See screenshots).
After updating the settings please restart your host.
If any program like "Little Snitch" is used, please ensure a connection to the IP address 226.0.0.1 is allowed. This is a multicast address used for inter-plugin communication.