Why did not write Nlog to targets

In  NLog.config write nlog tabs; throwExceptions="true" internalLogFile="c:\nlog.txt" internalLogLevel="Trace" 

like;

<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" throwExceptions="true" internalLogFile="c:\nlog.txt" internalLogLevel="Trace" >