bounces
Mailbox full: Not always an inbox problem
When an email bounces back with a "mailbox full" or over-quota SMTP rejection, the standard assumption is that a subscriber has le...
Topic
bounces
ask al
Troubleshooting 4 different types of Microsoft DKIM rejections
If your attempts to send email to Microsoft-hosted inboxes are bouncing back intermittently with authentication-related rejections; specific...
bounces
Help! I'm seeing 550-5.7.25 errors at Gmail!
Are you seeing this error message when trying to send emails to Gmail? 550-5.7.25 The IP address sending this message does not have a PTR re...
bounces
Holiday mid-season check in: What DMARC data reveals about BFCM delivery challenges
Webinar alert! You've survived Black Friday and Cyber Monday, perhaps Giving Tuesday, too, maybe it ended up stretching into Cyber Week,...
ask al
SPF fail, DKIM pass, DMARC pass: A confusing Microsoft rejection
Here's a confusing rejection that an email sender asked me about the other day. It's a Microsoft OLC (Outlook Consumer, aka Hotmail ...
bounces
Yahoo Mail reduces default free storage to 20gb
As reported here and elsewhere , Yahoo has reduced the amount of free storage for Yahoo Mail users. The prior limit, 1 terabyte, is now redu...
bounces
Cool tool: SMTP Codes
Here's a simple-but-cool tool created by Faisal Misle : smtp.codes . smtp.codes is a collection of SMTP response codes returned by emai...
bounces
SMTPUTF8 Errors and Bad Encoding: A Story
Has this ever happened to you? Because it just happened to me! In theory, I should be on top of this sort of thing, because I've been wr...
att
Seeing AT&T Reverse DNS issues when sending mail?
Example SMTP Errors When sending email messages to the various AT&T consumer email domains (ameritech.net, att.net, bellsouth.net, curre...
bounces
550 5.4.1? It (most often) means User Unknown
I've blogged about this before, covering the different types of NDRs (non-delivery reports, aka bounces or rejections) that you receive...
bounces
Tuesday Tip: When your message is too old
Have you ever run into the SMTP bounce message "too old"? Perhaps with a status code of 602? Here's what that means! This isn...
best practices
Tuesday Tip: Understanding Bounces
Bounces (also called Non-Delivery Reports /NDRs or SMTP rejections) happen when you attempt to send email to a recipient and that attempt fa...
bounces
Tuesday Tip: Gmail doesn’t discard!
Time for another Tuesday Tip here on Spam Resource. Tuesday Tips are meant to be short little bits of wisdom, easily digestible deliverabi...
blocking
Gmail rejection: Your sending IP address is not authorized
If you're trying to send email using an email server hosted on an IP address not expected to be running a mail server, your attempts to...
authentication
A sampling of DMARC rejection examples
My loss is your gain! I accidentally fumbled my DMARC record temporarily – locking everything down just a little too well for one of my doma...
bounces
Gmail error: IP not authorized
If you're trying to send email using an email server hosted on an IP address not expected to be running a mail server, your attempts to...
bounces
Use this one weird trick to ensure full domain alignment in SFMC
Here's a tip that I think Salesforce Marketing Cloud users will find useful, especially in the context of the new Yahoo and Google sende...
bounces
All the different bounces you can get from O365
Bounce message. SMTP rejection. Deferral message. Non-delivery report (NDR). 5xx error. 4xx error. No matter what you call them, there are ...
blocking
Gmail: New spam-related rejections and what you need to know
Gmail has very recently unveiled a series of new deferral/rejection messages. You may want to familiarize yourself with the following new SM...
bounces
Microsoft: Multiple types of invalid user bounces
Sending mail to Microsoft domains can mean you get different types of bounces back for what is effectively the same problem. Check out these...