Read the log yourself. It clearly says the server token was used somewhere else.
Code:
****************************************************
* *
* Steam account token was reused elsewhere. *
* Make sure you are using a separate account *
* token for each game server that you operate. *
* *
* To create additional game server accounts go to *
* http://steamcommunity.com/dev/managegameservers *
* *
* This game server instance will now shut down! *
* *
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