Hi, using Exchange 365 and GMAIL is bouncing all emails -- unsolicited email from your IP address

I did all the domain checks and everything is checking out fine. SPF and reverse DNS are all correct.

"Remote server returned '550 5.4.300 Message expired -> 421 4.7.28 [2a01:111:f403:7052::701 15] Our system has detected an unusual;rate of unsolicited mail originating from your IP address. To;protect our users from spam, mail sent from your IP address has been;temporarily rate limited. Please visit; https://support.google.com/mail/?p=UnsolicitedRateLimitError to"

Is there a problem on the MS IP addresses right now?

I'm seeing the same exact thing. It's been happening on and off for a while now. We didn't know it wasn't happening until we started hearing that some users weren't receiving their emails. Users that use small email providers like AOL and local ISPs report they receive all emails and the test emails I've been sending out. Only gmail users seem affected.

Hi G1030

Thank you for posting in the Microsoft Community forum. I hope you're doing well.

I am sorry to hear that you have a problem with sending emails wherein Gmail is bouncing back your emails. There could be possibly an issue with the ISP server causing your emails to bounce back. Let's work together to find the best solution to this problem.

I would like to ask some questions to better understand the problem.

• Can you tell which specific account has the problem? Just provide us the domain if it's @outlook.com, @hotmail.com or something else.
• How do you access your email? Is it through the Outlook mail app or on the Outlook.com web?
• Is it only Gmail account that you're having problems with sending emails?

I look forward to your reply.

Sincerely

ReynaldoB

Microsoft Community Forum Moderator

Hello!

We haven't heard from you in 72 hours, so we assume that your issue has already been resolved. We will not be monitoring this thread moving forward so, if you need further assistance, please create a new thread to discuss these concerns by clicking this link: Create a new question or start a discussion (microsoft.com)

Thank you for your understanding. 

Sincerely

ReynaldoB

Microsoft Community Forum Moderator

We're seeing this as well.

Can send to individual GMAIl users, but not more than one CC or BCC.
Same error message as above. Started happening around 9th of September, so looks like Microsoft IPs have been spamflagged.

To rule out the IP address as a possible issue, I had the user send test emails from her iPad, iPhone (native mail settings) and I also from her windows laptop via office.com and all of the results are the same. It only seems to happen with Gmail recipients. I also ran a message trace in O365, and the results show delivered for some and pending for others and the user receives a undelivered email notification 24 hours later. There is also a mix of delivered and pending in the trace message window, so not all Gmail recipients are marked as pending.