The next version of MailShot is coming very soon.
It features greatly increased compatibility with a range of mail servers, which will help a number of people who contacted us for support on this in the past week (thanks to all of you for your involvement.)
We cover the issue in more detail on our support pages, but if you should experience issues sending to your MailShot groups (such as server error messages, or certain people unable to “reply all”) on your system, please try using the Contacts app to send your group mail if you can, just as a temporary measure until the free update is available.
Soluble Apps 