When using MAILTOOL Plus (whether with MAILTOOL or SPL2EMAIL) turning on debugging is as easy as specifying DEBUG(*YES) on the MAILTOOL or SPL2EMAIL command.  In fact, newer versions don't need to specify DEBUG(*YES) to provide a trace when an error occurs.  It will automatically have the debug info available.  And if you're on the most current version (at the time of this, v12.50 sp221204) the job log will actually contain the full name of the trace file that we will need.

Once the command completes, there should be a trace file (and possible other files) in the IFS that can assist with debugging.

The file you will want to either examine, or forward to me for help, is the following:

/tmp/mailtoolsmtp_xxxx.txt

Where xxxx is a sequential and unique email ID.  If you are on an older version of MAILTOOL then the file will simply be named /tmp/mailtoolsmtp.txt (and you should think about downloading and updating to the latest version(s) of any software of ours you have installed.  It's free or any licensed partition!).

You can either transfer the file to your PC to forward to me using Operations Naviator, Windows Explorer (if you have NetServer and up running and a share to the /tmp directory), or FTP.

This file will contain a full trace of the communications between your IBM i and the mail router you are using. 

If possible, please also send a job log in text or PDF format.  

And finally, please send the version of MAILTOOL.  That can be found using this command:

DSPDTAARA DTAARA(MAILTOOL/MAILTOOLV)