I suspect this might have something to do with your email provider . Groups.io seems to have issues with some of the services. Since the problem of the bouncing is not universal, there has to be some cause on your side. Which email client are you using and what is your provider?
From: Pastor Gil Pries
Sent: Tuesday, August 6, 2019 12:41 AM
Subject: [jaws-users] My Account
My account keeps bouncing.
I go to the groups.io and unbounce it, but it goes back to a bounced condition.
Can you guys check it on your end?