Here is more information.
Here is the strange thing. When I create a mailing list called "haha", it works fine. When I create a mailing list called "supportt" with the extra t, it works fine. Local and external emails get the emails.
When I create a mailling list called "sales" or "support", it does not work. Local emails cannot get the emails and external emails can get the emails.
Very strange. It must be something I did but I cannot remember where I have messed up.
Please advice what I can do to rectify this. Please help.