[Mailman-Users] email subscribe command not responding

[Walt Thiessen]

I have a list where the email command to subscribe another user doesn't 
seem to work when I include it in the body of an email and send it to 
mylist-request at mydomain.tld.

subscribe [$<$PASSWORD$>$] [digest|nodigest] [address=$<$ADDRESS$>$]

When I try to use it, I get no notification back of any kind.

is there a setting somewhere that might be affecting this functionality?