Index: trunk/src/org/openstreetmap/josm/gui/MainApplication.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/MainApplication.java	(revision 15320)
+++ trunk/src/org/openstreetmap/josm/gui/MainApplication.java	(revision 15321)
@@ -1216,4 +1216,5 @@
                 } catch (IOException | SecurityException e) {
                     Logging.debug("Exception while checking IPv6 connectivity: {0}", e);
+                    hasv6 = false;
                     Logging.trace(e);
                 }