Fallback to usable addresses only

app/src/main/java/eu/faircode/email/EmailService.java

@@ -417,19 +417,21 @@ public class EmailService implements AutoCloseable {
                         if (iaddr.equals(main))
                             continue;
 
-                        if (!vpn) {
                         if (iaddr instanceof Inet4Address) {
-                                if (ip4 || !has4)
+                            if (!has4)
+                                continue;
+                            if (!vpn && ip4)
                                 continue;
                             ip4 = true;
                         }
 
                         if (iaddr instanceof Inet6Address) {
-                                if (ip6 || !has6)
+                            if (!has6)
+                                continue;
+                            if (!vpn && ip6)
                                 continue;
                             ip6 = true;
                         }
-                        }
 
                         try {
                             EntityLog.log(context, "Falling back to " + iaddr.getHostAddress());