The Issue

On the Expression app, in the main screen for your selected service, the contribute button is missing.

The Reason

The two main reasons for this issue is that there is not a live data connection or the contributions functionality is not turned on for the service.

The Fix

1. If the returning guest button is there, the contribution functionality is more than likely not enabled on the dashboard. Check the service details on the Expression Dashboard to make sure it has “contributions” enabled for that service. (By default contributions are off).  If contributions were not enabled for the service, you will need to refresh the Expression app.
   
2. If contributions were enabled on the dashboard, check to see if you are connected to a data connection on the Service Selection screen. If reception is poor, or you do not have a data connection available, the button will not be there.