DNS problems, email notifications not being sent

I had a working Open Media Vault system with notifications going out and then it stopped. OMV runs on Debian. In the log I started seeing: The actual error was: postfix/error[1443]: 1D96741676: to=<joe.blogs@domain.com>, relay=none, delay=175894, delays=175853/41/0/0.24, dsn=4.4.3, status=deferred (delivery temporarily … Continue reading