1	Confirm the user is logging into NBL via Revit with the correct username and password by logging into www.nationalbimlibrary.com and downloading an object from here.
2	Check that NBS Tools is installed.
3	Check the date, time and regional options are correct.
4	Check that the version of NBS Tools and NBS Plug-in are up to date and compatible. (We only support the 3 most recent versions of Revit) If in doubt uninstall both and reinstall with the user.
5	Ensure that the user has an NBS.bundle folder in C:\ProgramData\Autodesk\ApplicationPlugins with read/write/modify permissions.
6	Close Autodesk Revit
7	Reopen Revit and retry downloading an object.
8	If the config file has the NBS sections it has been updated and you should continue to troubleshoot. If it doesn't you should get the log file which the NBS developers can use to determine why the installation is not working as designed.
9	Log file is temp directory: %temp%\Pluginoutputlog.txt. An example from BDP is below:
10	Check that the firewall is not blocking www.nationalbimlibrary.com/auto-login as this uses a cookie from NBL to know who is downloading the object.
11	If the config file has been updated with the NBS sections check that the plug-in is not being blocked by a firewall or proxy server. It communicates with Services.ribae.com just like NBS Create but the user (as BDP had done) had specifically white listed the path that NBS Create uses and blocked other sub-domains of services.ribae.com
12	Does the same issue apply to other users and other machines at that company? To test this does it work on a machine 'off network'? Does it work for users with no proxy/firewall restrictions like an IT admin?