The Deal Breaker: Sending to groups still not functioning

What do you mean by, “Sending to groups”?

Also, do you have a link to the instructions you’re following?

If you mean adding/managing/using groups of Contacts, at my last check that wasn’t fully implemented, and it wasn’t implemented at all when using certain mail providers. See here:

However, sending to a large number of contacts is otherwise working fine for me through my third-party IMAP/SMTP provider.

(Reposted as a reply to OP)