diff --git a/os/net/mac/tsch/tsch-slot-operation.c b/os/net/mac/tsch/tsch-slot-operation.c
index 841dee07f850cce3999eade96fff1be8671b8ad1..a801bc92eeea4ae7eb648116e11b1d3619e6df68 100644
--- a/os/net/mac/tsch/tsch-slot-operation.c
+++ b/os/net/mac/tsch/tsch-slot-operation.c
@@ -643,6 +643,8 @@ PT_THREAD(tsch_tx_slot(struct pt *pt, struct rtimer *t))
             mac_tx_status = MAC_TX_ERR;
           }
         }
+      } else {
+        mac_tx_status = MAC_TX_ERR;
       }
     }