Service Communication Error: "an error append while trying to communicate with NextDNS Windows service".

I had the software of NextDNS on my computer and I uninstalled because of VPN anti-DNS leakage. However, currently I have installed it again, but I have got that error dialog above: "An error append while trying to communicate with NextDNS Windows service." – I have been searching for a solution online, but I did not find any useful one. Can I have a hand? I appreciate any effort to assist.