Try to get out your sailors when  server is half-empty( about 4:00 am server time should be good).In server prime time, i also get same message.Hope this help.

Thank you very much

i have same problem for one card No5 from my H.Q. I send suport ticket and waiting to answer.

should be lag, for me its item's tab that i can't connect too. like others suggested try when lesser people are online.

Who knows, I Can Take Sailors out, but when i try to deposit them back in the HQ i get an unknown error and they will not go back in.

One other thing that has had an impact in the past is logging in through less laggy servers - if they haven't been tried, many players have found one or another of the Chinese servers to lag less and provide better access to HQ. At one point, I even had one server I used for HQ, and another for playing.