Hello,

Does this problem still remain?

No

Hello,

If this problem still remain, you need to do the following:
stop the radmin vpn service
Control Panel \ All Control Panel Items \ Administrative Tools \ Service
find radmin right-click and select stop.
Run the cmd as administrator and enter
ipconfig / flushdns
Start the radmin vpn service
Control Panel \ All Control Panel Items \ Administrative Tools \ Service
find radmin right-click and select start.