I am sorry to hear that you are having problems with the App. Please let me know the type of devices you are using to download the App. Also visit this link to get the full list of compatible devices: Activision Support.
I was chatting to the clan last night and most of us are having the same problem..
And to add to the flame the servers where bad last night.. took us an hour to find a game only to be disconnected half way through...
and what made it worse was that the next hour was the same.. this was on PS4, you guys really need to look into improving that..
With the excitement that comes with new Clan Wars, there can sometimes be a throttle of users on the app. This might cause the Clan Wars section of the app to become a little unstable, thus resulting in what you are seeing.
While Beachhead are constantly doing what they can to improve performance, the best thing I can suggest during Clan Wars, is to keep checking back on the app for any changes.