To see what contacts have failed to upload to VerticalResponse and why, navigate to the VerticalResponse tab in your list. In the toolbar, select Actions and then View Rejected Records.
This will open a window in your browser with a list of contacts that have failed to upload from aACE to VerticalResponse during your most recent upload or sync, along with the reason why each contact was rejected. Contacts that have been deactivated, have an invalid email address, or have previously unsubscribed or bounced from VerticalResponse will not be uploaded. Note that a new report is generated each time you upload or sync contacts to VerticalResponse and is not cumulative.