It is possible that a user has signed out on the device. If this is the case, the user has to try signing in again. If signing in fails to work, an error message will appear Sign in failed! Try again (later) or contact us. The following things need to be checked if this occurs. 

1. Make sure that the device has a strong 3G, 4G or Wifi-connection. 

2. Make sure the username and password are spelled correctly. Perhaps @ or has been forgotten, the name might have been misspelled or the e-mailadress and/or password do not start with a capital letter. 

3. It is possible that the account is linked to too many groups or groups that are too large. This can be checked in the dashboard. If this is the case, the app will not be able to load the large amount of data and as a consequence it will stall       when signing in. 

4.Check in the Google Play Store or in the Google App store if there is a new update available for the app. Perhaps the device is running on an old version of the app. Always make sure that the latest version is installed. 

5. If signing in is still not working after having tried all of the above solutions, try deleting and reinstalling the app.