Hello!

Stop the Radmin VPN service (Control Panel - Administrative Tools - Service), find Radmin VPN Control Service, right-click and click Stop.

You need to run cmd(command prompt), press Win + R to open the Run window:

ipconfig /flushdns

Start the Radmin VPN service (Control Panel - Administrative Tools - Service), find Radmin VPN Control Service, right-click and click "Start".

If it does not help, repeat the procedure but after rebooting the PC, press ON OFF, wait about 15 or more, Radmin VPN need a time to register on servers, do not try to click often button ON/OFF .

if you have a router, please reboot it and Restart PC.

If you have still problems , send to us logs of Radmin VPN:

Open Radmin VPN - Help - View Log - File - Save As..-Save and send this file to us.