I have already written a post on SQL Developer connectivity problem. But recently I got one new error while connecting SQLDeveloper to remote database. First as I mentioned in my last post set proxy if you are using any in your SQLDeveloper and then try to connect it. But If it still gives the error then tried this workaround and I hope it will be helpful too. Sometime when we are connecting more than one internet connection due to any reason like client sides visit, home, office etc, our network connection get increased under network and sharing center and at a time more than one network remain Enable even if they are not connected to any network, so here comes the problem. Disable all of your network you are not using currently like I did in below screenshot and just Enable only network you are currently working with. After doing this try to connect your SQLDeveloper with remote DB again and it should work now and I hope it will be helpful too.
