Cannot connect to specific wi-fi network

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http://askubuntu.com – I was able to connect to my work wi-fi network normally without any issues. Suddenly after I have rebooted my laptop I was unable to join this specific network. I can connect to every other network and I can even connect to the company 2nd wi-fi network that has routers under the same manufacturer. I am able to connect to this network using different devices. Is there any possibility that my my mac address is banned from the router? My wi-fi icon just blinks and then drops the connection without any message. I am using Ubuntu 12.04. What can have caused that issue? (HowTos)