diff --git a/imaginaerraum_door_admin/door_handle.py b/imaginaerraum_door_admin/door_handle.py
index af46656..fc1e32a 100644
--- a/imaginaerraum_door_admin/door_handle.py
+++ b/imaginaerraum_door_admin/door_handle.py
@@ -92,15 +92,15 @@ class DoorHandle:
         if self.nfc_sock is not None:
             self.nfc_sock.send(b'rld\n')
 
-    def open_door(self, user=b''):
+    def open_door(self, user=''):
         if self.nfc_sock is not None:
-            self.nfc_sock.send(b'open ' + user + b'\n')
+            self.nfc_sock.send(b'open ' + user.encode() + b'\n')
         else:
             raise Exception("No connection to NFC socket. Cannot close door!")
 
-    def close_door(self, user=b''):
+    def close_door(self, user=''):
         if self.nfc_sock is not None:
-            self.nfc_sock.send(b'close ' + user + b'\n')
+            self.nfc_sock.send(b'close ' + user.encode() + b'\n')
         else:
             raise Exception("No connection to NFC socket. Cannot close door!")