Fix 1)
Please check the configuration file your game server is using, in your command line in your control panel --> Configuration Tab.
This should be something like: -r myconfig.cfg -m Napoleonic Wars
Where myconfig.cfg is your config file, please make sure this file is present and the correct server settings are set.
In case your game server still prompts an incorrect authorization key error, try step 2:
Fix 2)
Please stop your game server, leave it offline for 10 minutes, and then start it again.
There is some weird bug in Mount and Blade servers that they do not release its port binding sometimes which causes this issue.
In 90% of the cases this should fix the issue (make sure to really keep it offline for at least 10 minutes).
Last updated Mon 25 Nov 2013