I am having the same issue. I have had no problems since I first installed AIRvpn. As of today I am on a macbook and have tried everything possible that seems obvious including turning off the options in the "check if tunnel is working" etc. I have restarted the software, restarting the machine and still only gets as far as checking route. This is new as of today. My ISP is a cable company and Im not sure what else to tell you to help but Its just not working any more..
UPDATE... I was able to get the client to get and stay connected by turning off both of the options 1 "check if tunnel effectively works" and 2 "check if tunnel uses AIR vpn DNS ". My question would be now does turning these options off in order to maintain the connection affect the software's effectiveness ? Will this reduce security and possibly cause DNS leak ? and why did this happen after using the software with these options on for the past month with no problems. Thank you