Email Authentication: SPF, DKIM, and DMARC Best Practices
Outlook Deliverability: A Silent Shift with Serious Consequences
2025/06/20 by Yves-Marie Le Pors-Chauvel.
Starting on June 17th, 2025 at 11:10 UTC, multiple high-volume senders – particularly in France – began experiencing a sudden surge in DKIM failures on emails sent to Microsoft domains (Outlook, Hotmail, etc.). These bounces occurred even though SPF and DMARC were properly configured. UPDATE – July, 10 2025 Since the original publication of this […]
Categories: Authentication, Deliverability, Providers
Explore Postmastery’s New YouTube Channel Featuring Highlights from the Postmastery Day 2024 & EMAS.
2024/08/13 by Willem Stam.
We are pretty excited to announce the launch of Postmastery’s brand new YouTube channel, what we hope will be a hub for insightful and engaging content on email deliverability. Our first uploads feature sessions from the very first Postmastery Day at the Deliverability Summit, held at The Rosarium in Amsterdam on April 11, 2024. This […]
Categories: Authentication, General
All the bounce we cannot see: A Deferral story
2024/07/10 by Yves-Marie Le Pors-Chauvel.
When we work in email deliverability, we constantly hear about the processing of bounces, sometimes about blocking bounces and more often about suppressing bounces… In short, as you will have understood, processing bounces is the absolute prerequisite to email deliverability … But then, what about Deferrals… Should we process them? And if yes, how? What […]
Categories: Authentication, Deliverability, Deliverability
iCloud Postmaster(y) page
2024/03/14 by Syed Alam.
To help the sender community, we are glad to share our experiences collected over the years with some ISPs. This page is about the ICloud. – Market share and history of MBP – Anti-Spam Measures – Feedback Loop – Technical and SMTP tweaks – Common Error SMTP Messages – Abuse Desk & Tech Support
Categories: Authentication, Deliverability, ISP, Postmaster(y) ISP pages
Laposte.net Postmaster(y) page
2024/01/29 by Yves-Marie Le Pors-Chauvel.
In order to help the sender community, we are glad to share our experiences collected over the years with some ISPs. This page is about the main French Mailbox Provider: Laposte.net. This mailbox provider represents millions of active users and is the French biggest free Webmail. Postmastery integrates data from the aggregated Feedback Loop of […]
Categories: Authentication, Deliverability, ISP, Postmaster(y) ISP pages
Google & Yahoo’s February Bulk Email Policies: A Guide to Compliance
2023/12/14 by Yves-Marie Le Pors-Chauvel.
On October 3rd 2023, Google and Yahoo introduced new requirements to fight spam! This is a major change for the email industry, while, for the first time, two of the biggest Mailbox Providers announced commonly that they will apply the same restrictions to bulk senders. Who is concerned about it? For Gmail personal accounts (Gmail.com […]
Categories: Authentication, Deliverability, General
Gmail Postmaster(y) page
2023/11/23 by Syed Alam.
IMPORTANT UPDATE 23/11/2023: Since November 15, Google has changed many of its SMTP answers, this blog post has been updated with these new messages. In case of any need, please reach out to the Postmastery Team. To help the sender community, we are delighted to share our extensive knowledge and experiences gained over the years […]
Categories: Authentication, ISP, Postmaster(y) ISP pages