Only sending to 2 users

I manage a site for a not-for-profit organization of about 80 idividuals. We need to be able to allow members to send a message to the entire group, and I’d like to do so via the website using a contact form. I’ve installed Contact Form 7 along with Contact Form 7 Group Mail. While testing, everything seems fine, and messages are delivered to me, as the only member of the admin group. When I expand the selections to include all members, the form indicates that it was successful, but nobody is receiving messages. I suspect that one or two people are, but don’t know which (first few in the alphabet?). I don’t want to enter all the emails in a comma delimited format, since part of the reason of having the site is so that members can change their own email addresses, and this method would always send the message to the most up-to-date list.

Is Contact Form 7 capable of sending to more than 2 people? I’ve tested turning off Group Mail, I’ve installed SMTP plug-ins, nothing has solved this issue. Since I have another email plug-in that notifies the subscribers of new posts, and everyone’s getting those, I have to point the finger at Contact Form 7. Am I missing something?

https://www.ads-software.com/plugins/contact-form-7-group-mail/