error/bigbluebuttonbn/view error unable join
This error message is thrown when either of these three conditions occurs.
1. The BigBlueButton server is not available.
If you have an auto hosted server, try going to the BigBlueButton server main page and see if you can join to the Demo Meeting. You should have access through a page like the one shown here: http://demo.bigbluebutton.org/
The plugin comes preconfigured for start using BigBlueButton out of the box. If you are not sure if your BigBlueButton server is working right, try using these credentials:
URL: http://test-install.blindsidenetworks.com/bigbluebutton/ Secret: 8cd8ef52e8e101574e400365b55e11a6
2. The URL used in the configuration is not correct
The URL must follow the format shown as example in the configuration page. This means that it should include the schema or protocol (http://), the domain and port (or hostname) should be valid and it should be solved from the server, and the path should end with a slash (/bigbluebutton/)
3. The Shared Secret (aka Security Salt) used is not correct
It is a common mistake not to use the correct Shared Secret.
You can retrieve the API parameters (API endpoint and shared secret) using this command in your BigBlueButton server
You can find more references here http://docs.bigbluebutton.org/dev/api.html#api-security-model
Additionally you should verify that your Moodle server can communicate with the BigBlueButton server. You can do this by running this command in a terminal from your Moodle server.
you should be able to see the XML response in the console like this.