I've tested the setup package under some scenarios with high security settings and in a couple of cases, the bootstrap file was blocked.
Now, that script is a simple service checker. If the services aren't running, then it throws a message, but if everything is ok, then it launches Chromium.
So, if the tray menu properly started the services, you can skip the launch of the bootstrap file by:
1. Opening the D:\Program Files (x86)\SMTPing\SMTPing.ini with a text editor.
2. Comment line 105 by prepending a semicolon.
3. Uncomment line 106 by removing the semicolon at the beginning.
4. Save the file, close the tray app and start it again.
That's all you have to do :) ...you just won't have the startup service checker.