The fix is available in testing release 1.7.1-dev.2. Reload repositories from the Software Center page then you’d see the “Update to testing version” action in your Mail instance.
Additional information:
As alternative workaround, if further issues occur, the specific Mail update to 1.7 it can be temporarily be reverted the Postfix container version 1.6.4, by editing the MAIL_POSTFIX_IMAGE= line in theenvironment file, for example with
runagent -m mail1
sed -i 's|^MAIL_POSTFIX_IMAGE=.*$|MAIL_POSTFIX_IMAGE=ghcr.io/nethserver/mail-postfix:1.6.4|' environment
systemctl --user restart postfix # image download may require some time
Version 1.7 differs from 1.6 only in Postfix configuration templates.