Dear community,
please note that from the latest Updates provided beginning with today (2022-05-30) it is mandatory to have SSL enabled on the Admin API. For existing installations this might require an additional step executed with the latest updates, which is documented here: https://docs.grommunio.com/admin/operations.html#configuration
After an update, you might need to issue the following commands:
ln -s /etc/grommunio-common/nginx/ssl_certificate.conf /etc/grommunio-admin-common/nginx-ssl.conf
systemctl restart nginx