Redirecting log to json file using NLog - nlog

Question

In my organization we use UIPath and Robots logging is based on NLog. The default nlog configuration looks like:
<?xml version="1.0" encoding="utf-8" ?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<variable name="WorkflowLoggingDirectory" value="${specialfolder:folder=LocalApplicationData}/UiPath/Logs" />
<rules>
<logger name="WorkflowLogging" writeTo="WorkflowLogFiles" final="true" />
<logger minLevel="Info" writeTo="EventLog" />
</rules>
<targets>
<target type="File" name="WorkflowLogFiles"
fileName="${WorkflowLoggingDirectory}/${shortdate}_Execution.log"
layout="${time} ${level} ${message}"
keepFileOpen="true"
openFileCacheTimeout="5"
concurrentWrites="true"
encoding="utf-8"
writeBom="true" />
<target type="EventLog" name="EventLog"
layout="${processname} ${assembly-version} ${newline}${message}"
source="UiPath" log="Application" />
</targets>
</nlog>
It works but we decided to redirect logs also to json file. Now NLog.config file looks like:
<?xml version="1.0" encoding="utf-8" ?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<variable name="WorkflowLoggingDirectory" value="${specialfolder:folder=LocalApplicationData}/UiPath/Logs" />
<rules>
<logger name="WorkflowLogging" writeTo="WorkflowLogFiles" final="true" />
<logger name="ToJson" writeTo="jsonFile" />
<logger minLevel="Info" writeTo="EventLog" />
</rules>
<targets>
<target type="File" name="WorkflowLogFiles"
fileName="${WorkflowLoggingDirectory}/${shortdate}_Execution.log"
layout="${time} ${level} ${message}"
keepFileOpen="true"
openFileCacheTimeout="5"
concurrentWrites="true"
encoding="utf-8"
writeBom="true" />
<target type="EventLog" name="EventLog"
layout="${processname} ${assembly-version} ${newline}${message}"
source="UiPath" log="Application" />
<target type="File" name="jsonFile"
fileName="${WorkflowLoggingDirectory}/log.json"
layout="${longdate} ${level:upperCase=true} ${message}"
keepFileOpen="true"
concurrentWrites="true" />
</targets>
</nlog>
Now Robot doesn't log to any target. Any idea why?