diff --git a/owrx/form/receiverid.py b/owrx/form/receiverid.py
index 139bd82..28b7266 100644
--- a/owrx/form/receiverid.py
+++ b/owrx/form/receiverid.py
@@ -3,7 +3,7 @@ from owrx.form.converter import Converter
 
 class ReceiverKeysConverter(Converter):
     def convert_to_form(self, value):
-        return "\n".join(value)
+        return "" if value is None else "\n".join(value)
 
     def convert_from_form(self, value):
         # \r\n or \n? this should work with both.