VPN On Demand trigger success, but previous connection failed

I'm using mobile config to set up my VPN. I set up VPN On Demand successfully, now when I try to visit site "intranet address" using Safari, the rule matches, and VPN will start with no problem. The only question is: My first connection to "intranet address" will fail (Safari will show error page) even when my VPN connect successfully. It will only works after page refresh. Is there any way to not show the connection error page and wait for VPN start successfully?

Any advice is appreciated!