Send Folder Not sending

I just got the new Inbox 2. 1902.1.16980 and I notice that the Outbox is not working for only one email. I have a group called Los Amigos with three email addresses in it. I just discovered that I have been sending mail to that group for months which have never been sent. The group list looks fine but I get a big red exclamation mark on all these emails and a notice that "This folder is not currently synced."

Suggestions?

thanks

Len