Reports of Gmail delivery issues, such as spam bounce blocks and spam folder placement, have been increasing in the past 1-3 days. It appears to be affecting mail from Proofpoint, and Microsoft O365-hosted environments. To improve the situation, Gmail users should submit sample messages through the Gmail Sender Contact Form and ensure that their email messages are authenticated and wanted. Additionally, they should avoid cold emails, refrain from sharing domain reputation with others, and ensure their email system adds and handles necessary headers. Finally, this issue appears to have been resolved, although the exact cause is unknown.
Excerpt from the main article:
Multiple folks are reporting Gmail delivery issues today — both “571” style spam bounce blocks and spam folder placement. Some of the affected folks seem to be sending corporate mail, outbound from Proofpoint or Microsoft O365 hosted environments. It happens to some folks from time to time, but there are enough reports of it out in the wild that I think that perhaps Google released a significant Gmail filter update within the past 1-3 days and that it might be a bit buggy. It already sounds like some of those same folks are now seeing improvement. If you’re affected, be …
Gmail issues? You’re not alone was originally published on Spam Resource: All Things Deliverability