We use the ITThinx Groups plugin and are having the same problem. Emails to single users work but not groups.
Try going to settings/Email Users and set the BCC Limit to 1 (use To: field).
This will send a separate email to everyone in the group.
I think there’s something wrong with the BCC code when sending to groups.
Hi, thanks for answering
I had already tried that, but I still do not solve the problem, but I think it’s because of the firewall that I’m using, somehow blocking the sending of emails to outbound or incoming emails
It should be mentioned that my website is hosted on a private server
I should probably mention that the send to groups worked just fine for us for years until Jan/Feb 2017 (no problem with the basic setup and using Bcc).
There hasn’t been a change in how Email Users sends email. It has been the same for years. It is completely dependent on the wp_mail() function. Since it was working until a month or so ago, what else changed since then?
Thanks Mike, I will test on our staging site by disabling things and post my findings here.