I think Nabble were having problems with their n6.nabble.com server. It seems to be working now.
You do have to register separately on the Support forum. You wouldn't expect that anyone registering on another Nabble forum would automatically be registered on yours, would you? Bear in mind that your user name on your forum may have already been taken by someone on another forum.
Volunteer Helper - but recommending that users move off the platform!
Once the admin for GregHelp now deleted.