Try each of the following steps until the error is resolved:

 
     
    • Ensure the query in The Raiser's Edge that the list is based on has records in the results
       
    • Check that the email type on the Preferred Address of the records in the query matches the email type specified in NetCommunity (Administration > Sites & Settings > Phone Type Mapping) 
       
    • Recreate the list in Blackbaud NetCommunity
       
    • Recreate the query in The Raiser's Edge
       
    • Ensure that the email accounts have not been marked Invalid. Any accounts marked Invalid can be viewed and corrected in the Invalid Account Gallery.