How do I tell if mailman-web is running? There is no such service.
Which installation instructions did you follow from https://docs.mailman3.org/en/latest/install/install.html ?
If it was virtualenv (recommended) you have systemd services configured. Then run:
systemctl | grep mail
What does it show? Another method:
ps -ef | grep -i python
The mlist name is wrong. It should be lllllllllll%40gmail.com.
The mlist should be gmail.com?
Which official DNS domain are you using?
Usually mailing lists are set up on a DNS domain that you control. Are you an administrator of bellsouth.net or gmail.com? Or are those simply an end-user email account. You would register a domain with a registrar, and then create mailing lists on mydomain116.com, for example, or whatever the domain is.