You are only allowed to open your own kingdom if you have the correct login details. You wont be able to open silph's e.g. unless you have the login details. I would suggest you try the following which may help you. Check if PC is on. If not turn it on
Look at the thread by Thanatos-Korgano. It should be solved by using that thread's info. Otherwise I can forward/send you screenshots of what the devs emailed me to do to solve the issue.