Is this on the TurnKey Observium appliance? And if so, could you please clarify which particular version (i.e. the output of 'turnkey-version'). Plus also please share whether you have upgraded Observium to the latest version. If not, I suggest that you do that first (as per notes on the Observium appliance page).
If the issue still occurs, can you note whether you have set up a system-wide SMTP relay (e.g. via confconsole)? And if so, whether other emails are being delivered ok. Any other config modifications you've made to Observium would also be useful to understand.
Is this on the TurnKey Observium appliance?
Is this on the TurnKey Observium appliance? And if so, could you please clarify which particular version (i.e. the output of 'turnkey-version'). Plus also please share whether you have upgraded Observium to the latest version. If not, I suggest that you do that first (as per notes on the Observium appliance page).
If the issue still occurs, can you note whether you have set up a system-wide SMTP relay (e.g. via confconsole)? And if so, whether other emails are being delivered ok. Any other config modifications you've made to Observium would also be useful to understand.