diff --git a/src/include/taler_error_codes.h b/src/include/taler_error_codes.h
index 57dbd2db9..7e093c3ba 100644
--- a/src/include/taler_error_codes.h
+++ b/src/include/taler_error_codes.h
@@ -1229,6 +1229,13 @@ enum TALER_ErrorCode
    */
   TALER_EC_HISTORY_DB_FETCH_ERROR = 2201,
 
+  /**
+   * The backend could not find the contract specified
+   * in the request.   This response is
+   * provided with HTTP status code MHD_HTTP_NOT_FOUND.
+   */
+  TALER_EC_POLL_PAYMENT_CONTRACT_NOT_FOUND = 2250,
+
   /**
    * We failed to contact the exchange for the /track/transaction
    * request.  This response is provided with HTTP status code