@HB214 This problem was already described quite a while ago by other players here in the forum.
If I remember correctly, the admin´s response was that this is not a bug. It is how the game is meant to function. You cannot play offline/ in airplane mode.
Mittlerweile habe ich raus gefunden, dass dies öfters passiert, wenn man sich während des Spiels unter Optionen - Szenario und dann auf „ ?“ Die Regeln durchliest. Manchmal bereits nach dem ersten Mal. Oft dann nach dem zweiten Mal.
@richie_1@Rap0n This happens a lot at CU and a lot of players believe it is a server problem. Sometimes you can fix it yourself by login/logout several times. If not, write to support for help.
@V-Man That loss of cities happens according to the rules. Most players frown upon this strategy, and I personally dislike it, but it really is legit. Just find players who do not use this strategy, put them in your friend list, and you´ll be ok.
it.
It is how the game is meant to function. You cannot play offline/ in airplane mode. 
I'm SpicyKate. My friend Seeds would like to join too.
happens according to the rules. Most players frown 
upon this strategy, and I personally dislike it, but it really is legit. Just find players 
who do not use this strategy, put them in your friend list, and you´ll be ok.
!!....HORRIBLE...