MessageLogging Policy write to file - creates empty file

[#1]

Hi,

I have used MessageLogging policy in my PostClientFlow to log messages to a file ...I see the log file but not the message int it...The Files are empty can you please help

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<MessageLogging async="false" continueOnError="false" enabled="true" name="MessageLogging.LogServiceCalls">
<DisplayName>MessageLogging.LogServiceCalls</DisplayName>
<File>
<Message>This is a test message. Message id : {request.header.messageId}</Message>
<FileName>CRMApi.log</FileName>
<FileRotationOptions rotateFileOnStartup="true">
<FileRotationType>TIME_SIZE</FileRotationType>
<MaxFileSizeInMB>10</MaxFileSizeInMB>
<MaxFilesToRetain>10</MaxFilesToRetain>
<RotationFrequency unit="minute">10</RotationFrequency>
</FileRotationOptions>
</File>
<logLevel>INFO</logLevel>
</MessageLogging>