Testing Mailing list

Can someone let me know how to test a mailing list?
I am able to send messages to individuals, but when I try to send it to members@... or guest@...; noone gets my messages

Thanks!!!

Please provide your club number in each post so we can assist you better.

Please provide your club number in each post so we can assist you better.

876226.toastmastersclubs.org

Are you sending from the same email address as you have listed on the website?

Are you receiving an error message after sending?

I tried to send an email to the following two addresses:
"members-876226@toastmastersclubs.org"; "guests-876226@toastmastersclubs.org"

No error message and nothing got to anyone.
I did "CC" myself to a private email account I have and it I got the email, nothing went to anyone else.

I tested one email to only the "president-876226@toastmastersclubs.org" and that worked beautifully. Therefore, I can only assume that I can send emails to individuals (at least to the president - me), but all emails to the member or guest groups are not working.

Thanks for your help,

JM