diff --git a/DiscoverUM3Action.qml b/DiscoverUM3Action.qml
index 4daeaa1c37..5bac7d89ba 100644
--- a/DiscoverUM3Action.qml
+++ b/DiscoverUM3Action.qml
@@ -302,6 +302,10 @@ Cura.MachineAction
                 id: addressField
                 width: parent.width
                 maximumLength: 40
+                validator: RegExpValidator
+                {
+                    regExp: /[a-zA-Z0-9\.\-\_]*/
+                }
             }
         }