diff --git a/psycopg/connection_int.c b/psycopg/connection_int.c
index 7851b0a..feb4196 100644
--- a/psycopg/connection_int.c
+++ b/psycopg/connection_int.c
@@ -656,7 +656,7 @@ _conn_poll_connecting(connectionObject *self)
         break;
     case PGRES_POLLING_FAILED:
     case PGRES_POLLING_ACTIVE:
-        PyErr_SetString(OperationalError, "asynchronous connection failed");
+        PyErr_SetString(OperationalError, PQerrorMessage(self->pgconn));
         res = PSYCO_POLL_ERROR;
         break;
     }