diff --git a/src/serial.c b/src/serial.c
index b3c9a3bb3..7104f4ec0 100644
--- a/src/serial.c
+++ b/src/serial.c
@@ -680,6 +680,10 @@ int ser_open(hamlib_port_t *p)
             ret = OPEN(p->pathname, O_RDWR | O_NOCTTY | O_NDELAY);
         }
     }
+    if (ret == -1)
+    {
+        rig_debug(RIG_DEBUG_ERR, "%s: OPEN failed %d=%s\n", __func__, ret, strerror(errno));
+    }
 
     p->fd = ret;
     return ret;