Did not receive email when i register for an event

Hello,

As user I want to register to an event, after Filling the formulaire, I supposed to receive an email that I have registered for this event, however I didn’t not receive a confirmation email. maybe there are some config of the event that should be activated by admin?!

image

Thank in advance for your help,

Best regards,

What’s the URL to the event? If it’s not one managed by us you need to talk to the admin of that Indico server…

33rd European Synchrotron Light Source Workshop (ESLS) (29-31 octobre 2025): Welcome · Indico

you can register and check by yourself if you receveie email (only for sake of test, we will remove your inscritption after)

the email service is working for other part of application for your information.

I investigated the logs and found out this:

Use this setting to force Indico to use a sender address it can actually use in From. Probably it’s trying to spoof a sender which your mail server does not allow.

1 Like

Hello,

I have added this line of config to the indico.conf:

SMTP_ALLOWED_SENDERS = {
NO_REPLY_EMAIL,
SUPPORT_EMAIL,
PUBLIC_SUPPORT_EMAIL,
}
SMTP_SENDER_FALLBACK = NO_REPLY_EMAIL

it is working fine for version 3.3.7 (our test environment) but on our production instance (version 3.3.6) it does NOT work i have again this logs:

image

Thanks again for your help!

“Invalid recipients” is a different error. Maybe some people put invalid email addresses, and your mail server throttled you because you kept trying to send emails to them.

You need to check this with the operator of your mail server, they should hopefully be able to tell you what exactly caused it.

The log says “it contains no recipients”

Ah indeed, I only read the first part. Indico does not send emails with no recipients, so besides checking w/ your mailserver admins what exactly it received (assuming they have such data) the only option I see is adding some debug code to the mail sending code to log exactly what it’s sending to the mail server…

Hello,

Regarding the issue I mentioned in this ticket, we finaly found out that

the issue is coming from activating Attach an iCalendar file in the general setting of registration.

when we deactivate it, the user receive email after registration.

Thanks again for your attention,

Do you use Exchange by any chance? If you receive an ical file in an email coming from yourself it’s automatically moved to your trash folder. This should not result in any errors on the SMTP protocol level though.

Hello, I’m working with marcelin-8032, and we do use Microsoft Exchange for our mails. But I don’t know why the ical cause the whole thing to fail.

I only know that exchange likes to move emails from inbox to trash if they contain an ical file that’s coming from “yourself”…

Hum… weird, I did verify my trash when I was investigating, but I didn’t see a thing. And it can’t be it if the participants didn’t receive the mails that were sent by Indico.

For now we choose to not use the ical option, it’s safer that way :joy:

Maybe it’s unrelated and you have something blocking certain emails with ical attachments?

Maybe, we’ll try to see. Thanks.