UPS email alerts (APC, Eaton and others) with Microsoft 365

A UPS that cannot email you about a power event is a UPS you find out about too late. Network management cards on APC, Eaton, Riello, Vertiv and CyberPower units all send plain SMTP, usually without TLS, and Microsoft 365 no longer accepts it.

What the device needs

SMTP server: the SMTP-365 appliance's IP address, on your LAN.
Port: 2525 (or 25 if the device cannot change its port).
Authentication: none. Encryption: none. The relay is plain SMTP on the LAN and does the secure part to Microsoft itself.
Sender address: a real mailbox in your tenant (a shared "alerts" mailbox is free). The appliance can override it so every alert comes from the same address.
The device's address or subnet must be on the appliance's devices list (Settings → Devices).

Where the settings are

APC Network Management Card (NMC2/NMC3)

Configuration → Notification → E-mail → Server: SMTP Server = the SMTP-365 appliance's IP address, Port = 2525, Authentication = disabled, Use SSL/TLS = Never, From Address = the scanner or alerts mailbox. Recipients under E-mail → Recipients; use Local SMTP Server as the route.

Eaton Network-M2 / M3

Settings → SMTP (or Notifications → Email): Server = the appliance, Port 2525, Secure SMTP off, Authentication off, Sender address set. Add subscribers under Email notification.

CyberPower RMCARD

Notification → E-mail: SMTP server, port, authentication off, no SSL.

Riello NetMan, Vertiv IntelliSlot

Email or SMTP settings page: server, port, no authentication, no encryption, sender address.

Alerts should go to a distribution group or shared mailbox that more than one person watches. Because the appliance sends as a real mailbox in your tenant, the alerts land in Outlook as internal mail, never in Junk.

If the test message does not arrive

What you see	Likely cause	Fix
Connection failed / cannot connect to server	Wrong relay address or port, or the device's subnet is not in the relay's allowed sources	Check the address and port; on the appliance, Settings → Devices, add the device's subnet
554 5.7.1 Relaying denied (or the connection closes at once)	The device's IP is not among the appliance's devices	Add the address or subnet under Settings → Devices on the appliance
Authentication or certificate error on the device	Authentication or TLS is still switched on in the device	Set authentication to none/off and SSL/TLS to off; the relay is plain SMTP on the LAN
Device says sent, nothing arrives	Delivery to Microsoft 365 failed and the job is held or failed	Open the appliance's Status page: held and failed jobs show the reason and can be re-queued
Arrives, but from the wrong address	The device's own From address is being used	Turn on the sender override on the appliance so every message is sent from the scanner mailbox

One appliance for all of them

The same SMTP-365 appliance that fixes the printers takes the UPS, the servers' management cards, the NAS and the phone system, on one licence with no per-device fees. Each device gets the same three settings and the appliance's Status page shows every message it handled. Background: what Microsoft changed.

Fix it once, for every device. SMTP-365 is a small appliance on your network that accepts plain SMTP from printers, UPSs, servers, NAS and phone systems and delivers it into your own Microsoft 365 tenant with modern authentication. One licence covers every device on the site. Download the free 30-day trial See pricing

Updated 2026-10-10. Menu names and screens vary between models and firmware versions; if yours differs, look for the same fields under the device's email, SMTP or notification settings. Corrections welcome at helpdesk@smtp-365.com.