UiPath Alert Mails not working since last update

Feedback Orchestrator
, ,
1

Hi,

I have recently updated the Orchestrator with the version 25.10.3 and since this update, the alert mails are not working anymore. I have looked the Mail settings section and tried to delete / insert again the SMTP settings and I have this error message:

image
image755×188 7.7 KB

I don’t really understand why it causes an error, and especially because all the e-mails that are sent through my robots are perfectly working. It is just the Alert mails that don’t work anymore. Do you have an idea how to resolve this issue ?

Thanks,

Best regards

3

Root cause: “No such host is known” is a DNS resolution failure on the Orchestrator server itself — not an SMTP authentication or credentials problem. Orchestrator cannot resolve the hostname you typed into the Mail Settings box.

This is exactly why your robot emails still work: those Send Mail activities run on the robot machines, which resolve your SMTP host fine. Alert mails are sent by the Orchestrator web app, from a different server (and, in 25.10, often from a different service account / container network).

Step 1 - Prove it from the Orchestrator server (not your PC):

nslookup smtp.yourdomain.com
Test-NetConnection smtp.yourdomain.com -Port 587
If nslookup fails, you’ve confirmed the cause.

Step 2 - Apply the permanent fix based on what you find:

  • Short name used (e.g. mailserver instead of mailserver.corp.local) → always enter the full FQDN in Mail Settings. After an upgrade the DNS search suffix is frequently lost, so short names stop resolving.
  • FQDN doesn’t resolve at all → add the correct DNS server / suffix in the Orchestrator server’s network adapter settings, or have your network team add the A record. Using a raw IP address works as a stopgap, but will break TLS certificate validation, so fix DNS properly.
  • Orchestrator 25.10 running in Kubernetes/containers (Automation Suite) → the pod uses cluster DNS, not the host’s. Add the SMTP host to the CoreDNS custom hosts entry, or expose it via an ExternalName service. This is the most common cause after a 25.10 upgrade.
  • Hidden character in the field → don’t paste; retype the host manually. A trailing space or non-breaking space pasted from a document produces this exact error.
  • Outbound proxy in play → .NET 8 (used by 25.10) handles proxy settings differently than older versions. Confirm the proxy config in appsettings.Production.json and whitelist the SMTP host.

Step 3 – After changing DNS or config:
Restart the Orchestrator app pool / IIS (or restart the Orchestrator pod), then re-enter and save the SMTP settings and test again. Orchestrator caches DNS lookups, so a restart is required for the change to take effect.

Also verify: in 25.10 the Mail Settings must be configured at the Host level for system alerts; tenant-level settings only cover tenant-scoped notifications. Re-check that the host-level entry survived the upgrade and that the password was re-saved (passwords are frequently blanked during major version upgrades).

4

Hey @melanie

sometimes updates can mess up the smtp settings in orchestrator.

you should check the tenant settings under mail to see if your smtp config is still there and correct. also try to send a test email from that screen to see what error it gives you.

another thing to check is your user profile settings. just go to your preferences and make sure the alert subscriptions didnt get turned off by accident during the update.

hope this helps you out!

5

Hi,

I have contacted the UiPath support. Here is their answer, in case someone else has the same issue:

This is a known issue in Orchestrator 25.10 affecting on-premise installations, where the Identity Server routes SMTP connections through a proxy client even when no proxy is configured. A fix is being prepared internally. In the meantime, there is a confirmed workaround.

To apply it, please ask your server administrator to do the following on the Orchestrator server:

  • Locate the Identity Server installation directory, which is the Identity subfolder inside your Orchestrator installation folder
  • Open the file named appsettings.Production.json in a text editor
  • Add the following line inside the root JSON object: “UseSmtpClientProxy”: false
  • Save the file
  • Perform an IIS reset

Best regards,