There still seems to be a version difference from what I have. I see no code that generates this message:
8/5/2019 9:09:37 PM - Send Message : This operation cannot be performed while a message is being sent.
1) View the MessageHandler code
2) Ctrl-F to search
3) Search for "- Send Message", then tell me what line and file it goes to.
In the files I have, there is no match, so I am unable to find where that error originates.
Maybe that is the old remnants. Delete the ErrorLog.txt, then run again to generate a new one.