diff --git a/os/net/mac/tsch/tsch-slot-operation.c b/os/net/mac/tsch/tsch-slot-operation.c
index 5fbf8601392129a4ed8a6a6100dc225af9a40f41..a801bc92eeea4ae7eb648116e11b1d3619e6df68 100644
--- a/os/net/mac/tsch/tsch-slot-operation.c
+++ b/os/net/mac/tsch/tsch-slot-operation.c
@@ -643,7 +643,7 @@ PT_THREAD(tsch_tx_slot(struct pt *pt, struct rtimer *t))
             mac_tx_status = MAC_TX_ERR;
           }
         }
-      }else {
+      } else {
         mac_tx_status = MAC_TX_ERR;
       }
     }