There are two things to check that normally sort this out:
- Are you using the right email address? Perhaps you opened the account with your work email or vice versa? Alternatively, you might have previously logged in via Facebook.
- Is the time on your phone set correctly? If the clock is set to run fast (so you're not late for meetings) it will not allow the app to open. You may have to adjust the time on your phone back to the default.
If neither of these things explain the problem try uninstalling the app and then reinstalling it.
If you are still stuck, please drop us a quick email and we'll get right back to you.