RouteGadget uses Java which has come under pressure as an insecure product. Oracle has, therefore, tightened security on Java which means that RouteGadget probably won’t be allowed to run in your browser. (It would cost RouteGadget about £150 p.a. to get a certificate to allow it to run!).
There is a new version being developed that doesn’t use Java, but it is still in early stages. However, I hope to start to use this in the near future in parallel with the existing Java version.