The mailing list for listmasters using Sympa

[Mathieu Roquefort <address@concealed>]

Hello,

We’ve just have the same thing, with O365.

No idea of the cause yet, we begin investigating.

But you confirm that there is an issue between Microsoft and Sympa, and that’s pretty new (les than 1h).

Regards,

Mathieu Roquefort
Chef de projet internet
Secours populaire français
Tél. : 01 44 78 22 05
9/11 rue Froissart - 75140 Paris cedex 03
secourspopulaire.fr

    

De : address@concealed <address@concealed> de la part de Boyle, Brian <address@concealed>
Date : mardi, 16 décembre 2025 à 16:36
À : "Christian H. Kuhn" <address@concealed>
Objet : [en@sympa] List E-mails Tagged as "Unverified" in MS Outlook

We run a sympa service that is DMARC compliant, but are suddenly seeing a number of list e-mails being tagged in Microsoft Outlook as “Unverified” e-mails, with a banner on the e-mail stating, “We can’t verify that this e-mail came from the sender so it might not be safe to respond to it”.

 

This might be related to List e-mails in general, and in the case of sympa specifically, showing up as Sent ‘by Listname-Request on behalf of Listname’

 

Anybody else seeing this with Exchange and/or find a workaround? It seems to be new behavior that has just hit Outlook Online and newer Windows Outlook clients.

 

Brian