Steve on 18 Oct, 2018 10:24 AM
welcome to the GPGTools support platform. Sorry you are having problems using GPG Suite.
Please excuse the late reply, we are deeply sorry for not responding earlier. The amount of feedback we received in regards to the GPG Suite 2018.4 release was overwhelming - both positive and negative. We are doing our best to catch up as fast as we can.
We do not develop Mailmate nor the plugin for that mail client.
Regarding Mail.app and GPG Mail, could you send a screenshot of the error message you are seeing there?