There has been some problem. I saw another user reporting the same problem. Send a support ticket.
I highly recommend you to use a different app because Coinbase is not secure. Some of the wallets I recommend are
Bitcoin Wallet,
Bither,
GreenAddress and
Mycelium.
not secure from
i use coinbase more than 3month and iam not get any security issue
and perfect connect in web browser
only can't connect in coinbase android app
You have *no* control over private keys.
Do you create your own account to save your balance or will you tell someone else to create account, tell him/her to deposit and withdraw money when you want? You won't. Coinbase can easily steal your money and don't forget Mt. Gox.