Targets not configured for logger. Linux + MONO - nlog

Question

I'm using NLOG with Linux + MONO ASP.NET WebService and I'm not able to log two different file.
ASMX file have two different methos and I would like to log in separate logging file
This is Nlog.config
...
<targets async="true">
<target name="sendMail" xsi:type="File" fileName="${logDirectory}/${shortdate}_sendMail_${level}.log"
layout="${time} ${uppercase:${level}} ${message}" />
<target name="checkMail" xsi:type="File" fileName="${logDirectory}/${shortdate}_checkMail_${level}.log"
layout="${time} ${uppercase:${level}} ${message}" />
</targets>
<rules>
<logger name="sendMail" minlevel="Debug" writeTo="sendMail" />
<logger name="checkMail" minlevel="Debug" writeTo="checkMail" />
</rules>
</nlog>
This is the log file:
2020-04-20 01:42:39.6781 Debug LogFactory Flush with timeout=15 secs
2020-04-20 01:42:39.6907 Debug FileTarget(Name=sendMail_wrapped): Process file '/var/log/wsMail/2020-04-20_sendMail_Info.log' on startup
2020-04-20 01:42:39.6907 Debug FileTarget(Name=checkMail_wrapped): Process file '/var/log/wsMail/2020-04-20_checkMail_Info.log' on startup
2020-04-20 01:42:39.7058 Debug Creating file appender: /var/log/wsMail/2020-04-20_checkMail_Info.log
2020-04-20 01:42:39.7058 Debug Creating file appender: /var/log/wsMail/2020-04-20_sendMail_Info.log
2020-04-20 01:42:39.7442 Debug Flush completed
2020-04-20 01:42:39.7442 Info Shutdown() called. Logger closing...
2020-04-20 01:42:39.7442 Info Closing old configuration.
2020-04-20 01:42:39.7442 Debug LogFactory Flush with timeout=15 secs
2020-04-20 01:42:39.7442 Debug Flush completed
2020-04-20 01:42:39.7442 Debug Closing logging configuration...
2020-04-20 01:42:39.7490 Debug Closing target 'AsyncWrapper Target[sendMail](File Target[sendMail_wrapped])'.
2020-04-20 01:42:39.7533 Debug Closed target 'AsyncWrapper Target[sendMail](File Target[sendMail_wrapped])'.
2020-04-20 01:42:39.7533 Debug Closing target 'File Target[sendMail_wrapped]'.
2020-04-20 01:42:39.7585 Debug FileAppender Closing Invalidate - /var/log/wsMail/2020-04-20_sendMail_Info.log
2020-04-20 01:42:39.7620 Debug Closed target 'File Target[sendMail_wrapped]'.
2020-04-20 01:42:39.7620 Debug Closing target 'AsyncWrapper Target[checkMail](File Target[checkMail_wrapped])'.
2020-04-20 01:42:39.7620 Debug Closed target 'AsyncWrapper Target[checkMail](File Target[checkMail_wrapped])'.
2020-04-20 01:42:39.7639 Debug Closing target 'File Target[checkMail_wrapped]'.
2020-04-20 01:42:39.7639 Debug FileAppender Closing Invalidate - /var/log/wsMail/2020-04-20_checkMail_Info.log
2020-04-20 01:42:39.7639 Debug Closed target 'File Target[checkMail_wrapped]'.
2020-04-20 01:42:39.7639 Debug Finished closing logging configuration.
2020-04-20 01:42:39.7639 Debug Stopping file watching for path '/var/www/wsMail' filter 'NLog.config'
2020-04-20 01:42:39.7775 Debug Targets not configured for logger: sendMail
2020-04-20 01:42:39.7775 Debug Targets not configured for logger: checkMail
2020-04-20 01:42:39.7775 Info Logger has been closed down.
This is the code in VS2019
<System.Web.Services.WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)>
<ToolboxItem(False)>
Public Class wsMail
Inherits System.Web.Services.WebService
Public Credentials As AuthHeader
Public smLog As NLog.Logger = LogManager.GetLogger("sendMail")
Public cmLog As NLog.Logger = LogManager.GetLogger("checkMail")
Public messageID As String = Nothing
Public retMsg As String = Nothing
Public retRemoteMsg As String = Nothing
......
cmLog.Error("|" & idCustomer & "|" & remoteIP & "|wrong Password|")
smLog.Debug("- v1.0.1 |" & idCustomer & "|" & remoteIP & "|" & ex.Message & ex.StackTrace & "|")
Any help is appreciated, thanks a lot