@mention doesn't send message via apprise (azure) nor SMTP (we get error)

[FWPHVRS]

Hi.

First of all, congratulations on the v2.0.0 release.
We were particularly looking forward to the @mentions.

After successfully upgrading, I hade some issue with mailing updates and mentions.
We run planka together with some other tooling on our private cloud and have an exchange connector (direct mail sending via port 25) to allow mails being sent from internal services.

I've done the following things:

• Whitelisted the outlook mail host.
• Removed SMTP vars from container file (podman)
• Added the SMTP settings via the GUI.

This allowed me to send a test message. (this works)

Then I went to a card and did a @mention and then it doesn't send, I see this error:

2026-02-16 19:00:39 [E] Error sending email: Error: Can't send mail - all recipients were rejected: 550 5.4.1 Recipient address rejected: Access denied. For more information see https://aka.ms/EXOSmtpErrors

Subsequently I also added azure:// to apprise but that also doesn't seem to work, also not using the test button, I get error: 2026-02-16 19:08:10 [E] Error sending notifications:
[azure] There are no Email recipients to notify

Can somebody help out here to get me on the right track of what is going wrong or what am I missing here?

[meltyshev]

Hey! Thanks for the congratulations 🎉

I'm not very familiar with this myself, but I'll add a "help wanted" label and hopefully someone will know how to fix it.

[FWPHVRS]

Hello @meltyshev ,

Thanks for the reply. Let's hope then on more insights.
But you should be able to say something about why 'Send test emai' does result in an actual mail sent, but @mentioning somebody in a card leads to the mentioned error. This proofs that my connector works, just not from all areas of Planka.

[meltyshev]

Ah, sure. In the code, it uses the exact same SMTP transporter, just with much shorter timeout settings so it doesn't wait too long if the SMTP server isn't responding (but that shouldn't be the case here). The main difference I see is that with the test email - it sends the message to the current user (the one who pressed the test button), but for mentions and other real notifications - it sends to users who should receive the notification, either to their email address or to the provided service URLs (in the case of Apprise).

The SMTP error itself also indicates that the recipient's address was rejected. You can try logging in with a different account and mention your account (the user you used to test SMTP already, when it worked) - that way, it should work (of course, the mentioned user needs to have access to the card where they were mentioned).

[FWPHVRS]

Hi @meltyshev thanks for the quick reply. I think I understand what you are telling me, so I tested by tagging myself, which should lead to the same email address, which I can guarantee is known by our mailserver. But I still get the same error, actually with everyone of my team that has a valid email address. Any other thoughts? Or is there a debug setting that could give more information on this issue?

[FWPHVRS]

I also dived into the apprise azure link I've created. When I try to send email it says "[azure] There are no Email recipients to notify".. when I look in db that azure:// link is connected to my user id and in user tabel I see my email address. Might there be an issue with fetching the user email? It would explain also the error I get, because an empty recipient gets rejected.

[meltyshev]

Hi @meltyshev thanks for the quick reply. I think I understand what you are telling me, so I tested by tagging myself, which should lead to the same email address, which I can guarantee is known by our mailserver. But I still get the same error, actually with everyone of my team that has a valid email address. Any other thoughts? Or is there a debug setting that could give more information on this issue?

Yeah, this is very strange. I don't think there are more debug options on our side.

I was also thinking it might be related to the Default "from" setting - maybe the server doesn't allow sending emails with a custom "from" address, but in that case it should also reject the test email.

I also dived into the apprise azure link I've created. When I try to send email it says "[azure] There are no Email recipients to notify".. when I look in db that azure:// link is connected to my user id and in user tabel I see my email address. Might there be an issue with fetching the user email? It would explain also the error I get, because an empty recipient gets rejected.

Let me try testing it locally with my own SMTP server.

As for Apprise, I believe the full URL should already include everything needed to send the email - it should contain the SMTP settings and the recipient address, since we don't pass any additional data (like the user's email) to the Apprise binary when sending a notification.

[meltyshev]

When I trigger notifications, I see the following:

[server]  info: Email sent: <28301cc1-f45b-8a78-989c-7ff9b10156e8@localhost>
[server]  info: Email sent: <63bdfc7a-d954-7a8d-b224-78b59ace8a44@localhost>
[server]  info: Email sent: <861f26a8-2e86-52bf-679b-1d1c4d7c933d@localhost>

And I receive them normally at the user's configured email address. So it's likely something on the SMTP side. Is there any log available there that provides more details about the rejection?

[FWPHVRS]

We use this SMTP connector for all internal services, and it's working everywhere,except in Planka now (older versions worked, only since 2.0.0 it stopped working)

Does smtp go through proxy? SMTP goes straight to the mx endpoint on port 25 but if that would be the issue I would expect the test mail also to fail.

[meltyshev]

Does smtp go through proxy? SMTP goes straight to the mx endpoint on port 25 but if that would be the issue I would expect the test mail also to fail.

Yep, but it's enabled automatically only in the Docker version. It should still pass everything through itself, just like the request would without it (it's mainly there for security reasons). You can try disabling it by uncommenting OUTGOING_BLOCKED_HOSTS= and setting it to an empty value. If this turns out to be the cause, it'd be good to fix it asap.

UPD: ah yes, you are right, then the test mail should also fail as it goes via that proxy...

[FWPHVRS]

@meltyshev well I've tried disabling the proxy, and separately the outgoing settings like suggested. I need the OUTGOING_ALLOWED_HOSTS .. but still the test email works, but @mentioning myself doesn't lead to an email. What changed is that I do not see errors anymore in the logs, but unfortunately also no emails.

Update: on a card that does process the notification, I'm back at [E] Error sending email: Error: Can't send mail - all recipients were rejected: 550 5.4.1 Recipient address rejected: Access denied. For more information see https://aka.ms/EXOSmtpErrors [CP1PEPF00007752.BRAP284.PROD.OUTLOOK.COM 2026-02-18T21:25:34.139Z 08DE6BCC9B6B8530] , like mentioned the test email does work. There are no other errors or logs to be found.

[FWPHVRS]

@meltyshev and if I look in the database tables, I see my comment in the table "comment", but I don't see the @mention translated into a record in "notification" ("notification_service" stays empty).. It also looks like @mentions are everywhere possible but do not lead to an actual notification.. Does an @user need to be subscribed to board ?

I ask this because on another board, my @mention does get registered.. 3x times to be exact. Looks like there might be something nog going correct here.

[meltyshev]

There should be an in-app notification created when you mention someone (row in the notification table), and the sending happens immediately after it's created in the database. Also, mentioning should work even if the user isn't subscribed to the board/card, as long as the mentioned user has access to the card. Basically, you can verify it by checking whether the mentioned user received the in-app notification - then it was registered.

[meltyshev]

One more thought - could it be related to the email content itself? For example, the test email has simple text, but email with a mention contains "@" in the message.

Or does none of the notifications work at all, like when moving a card that a user is subscribed to?

[FWPHVRS]

@meltyshev I get no emails, except the test email. Not mention, not card move.
And it's not the SMTP end point, recheck on various ways, and everywhere the mail is accepted and delivered. Something changed towards v2.0.0. that leads to the result that I don't receive any notification emails anymore.