Sendmail not working


I have the email notification enabled and configured the health_alarm_notify.conf as below. But I’m not able to receive (Recipient Email - the email from the Email sender(

I’m receiving the warning\critical notification from to root users, but not from the configured email sender. And please help me with, How to disable this resolved/clear email message.

Could you please point me out what I might missed or did wrong? Thanks in advance.

Image My health_alarm_notify.conf looks like this: (edited)



Hi @ubs_netdata.

Just to make sure, are you sure your local sendmail is configured ok? For example, if you run from the same node that netdata runs, the following command, do you get an email? mail -s "Test Subject" < /dev/null

Hi Manolis_Vasilakis,

Have verified the above command from the netdata node and i didn’t receive any email, have shared the screenshot. PFA

Please help or share the detailed document to configure the local sendmail.

Thanks in advance.

Hi Manolis_Vasilakis,

Cloud to please help me with the below query.

What it means – Delay: down 15m multiplier 1.5 max 1h

First warning\critical notification has been received, and what is the interval time to receive the next second\third warning\critical notification? How to calculate it please help me out.

Hi @ubs_netdata ,

You can find detailed documentation on how to read the delay line here: Configure alerts | Learn Netdata

The documentation is extensive along with an example.


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Hi @ubs_netdata

Sendmail is somewhat hard to configure, but there are a lot of guides on the internet on how to setup. Personally I’ve gone with ssmtp which is much easier to configure locally.

I can’t share my personal config, but a good guide on how to setup can be found here → sSMTP - ArchWiki

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Hi Avrapa,

Thank you, will go through the document.


Hi Manolis_Vasilakis.

We will check on the sSMTP configuration and get back to you if still need any assistance.

And please help me with, How to disable this resolved/clear email notification.

Thank you!

Hi Manolis_Vasilakis.

Can we configure the sSMTP with our Office 365 ID?


Hi @ubs_netdata sorry, not sure if that works…

Hi Manolis_Vasilakis,

If any node is down, how I will get the notification? How to configure the down system notification.


Hi Dhananjay,

As per our DM chat on discord, if you are using Cloud this is already out of the box, you just need to ensure you have your notifications configured to send “Unreachable” notifications

this is on your User Profile → Notifications settings that is for the email notifications

can be “All Alerts and unreachable” if you want both or just “Unreachable”

If you don’t use Cloud you could rely on synthetic check like ping, you can read more about it How to monitor host reachability | Netdata Blog

Hi @ubs_netdata . This means that there will be a delay when the alert drops in severity (i.e. CRITICAL → WARNING → CLEAR). The delay will be 15 minutes, then for each time it drops severity it will delay for another 15*1.5 up until a maximum of 1h.

How you have set up the DEFAULT_RECIPIENT_EMAIL appears ok. The email will only receive Warning and Critical notifications.

HI Manolis_Vasilakis,

Have configured the email notification as above, but I am not able to receive the email notification from the recipient (Recipient Email -, and the Email sender(

I’m receiving the warning\critical\clear notification from to sysadmin users, but not from the configured email sender. please let me know where to configure the Office 365 SMTP for customise email notifications.


Hi @ubs_netdata

Sorry, but not sure about Office 365 SMTP . Likely you can configure ssmtp to use your Office server, but I’m not sure how it’s done. You likely need to setup mailhub to point to that server, as well as a valid username and password.

In the end, a basic test with the mail -s "Test Subject" < /dev/null should show if this setup correctly. If it is, Netdata will likely be able to use it as well.